You don't really want this color, cause this is going to show you what's really underneath all the pains which you've on a surface level been experiencing.  And why I say that you 'don't want this color', is because there's actually a conflict within you with yourself where you don't actually want to see reality. You're looking for solutions but you don't want to see what's really going on. You want the answers handed to you, but you don't want to look at the problems and figure things out yourself. So there is a disconnect with yourself, where you are basically making/living this statement that you don't actually care enough about yourself and that you will not give yourself attention. A statement of neglect of yourself. There is a sense of 'you do it for me! I don't want to be bothered with having to look at myself! I've been through enough. I've worked enough. I don't need to do anything anymore.' It's a refusal to put in any more effort, in a way as a result of cultural conditioning/programming.

The 'Chinese' culture of being worked to the bone, being used as a slave, and so you end up feeling like any additional 'work' that you have to do is just too much.  Like the 'work' of self-investigation and self-introspection. And in a way that makes you 'entitled', and angry. Angry in terms of 'having to deal with' things, things not being easy and not being handed to you on a golden platter. There is a sense of tiredness about things and an unwillingness to put any effort into for instance understanding things for yourself. It's like you've made a statement/decision that 'I'm not going to figure myself out. Somebody else must do this for me.' But you kind of miss the point of what 'support' actually is. Support is not 'somebody else will do it for you'. Support is, you do everything yourself, and there may be some perspectives others can offer you that could make things a bit easier for you. But there has to be that realization of responsibility for yourself, and there cannot be any excuse to not put in the work required to take on your own issues and change. 

Cause I can't give you all the answers. All I can offer is support. And support is always in the context of strengthening your ability to become the answers and to become the solution you've been looking for. To show you the tools or show you the way to be able to answer your own questions. Cause specifically the existential/emotional/mental pain is really your body and being's way of telling you that you need to 'pay attention!'  And the pain only intensifies as long as you are not giving yourself the proper attention. But YOU have to be the one. It has to come from you, the attention. You have to recognize your ability to get to the bottom of things and heal yourself. You have to start valuing yourself and putting in effort to get to know yourself. Start listening to your pain and start asking yourself what it might be showing you about yourself. Cause you won't so easily get away with just trying to get the answers elsewhere. It's not that easy. This is about your relationship with yourself. One you've been trying to avoid and get away from. One you never thought was important and one you thought you could neglect.

It's time to start getting real with yourself. Time to be ready to look at yourself, because even if I give you my perspectives and insights into your pains, it will be meaningless without you equally having a look. So let's then have a look at these issues you've been having. 

1. The rheumatoid arthritis: Has a lot to do with what I mentioned before, about being 'worked as a slave'. It is a generational/genetic programming of 'accepting oneself as over-worked'. Of 'living just to work' and 'giving up all of oneself for work'. Placing work before yourself, and so it is also related to the other point I mentioned about not giving yourself attention. Not seeing the importance in giving attention to who you are inside. So there is a high importance placed on 'working', not just in a practical sense, but in terms of your self-value and -purpose, as though 'all of you' is 'work' and it defines all of you. So I'd suggest to have a look at this point within you, of how much are you placing 'work' as more important than 'you', as well as using work as an excuse to 'not have the time' to pay attention to yourself. So this particular pain is about your inner relationship with 'work', and specifically how you use this relationship to sabotage your self-relationship and your ability to look inside.

2. Feeling pleasure from seeing other people's physical illness: So it is interesting that you have a relationship connection between 'pain' and 'pleasure'. This is not so much telling/showing you about 'who you are' in relation to other people or sexuality, but more about what is going on within you and this interesting relationship you have between pain and pleasure. Because your life/existence has been so much about pain, and it being part of your 'identity', your mind just uses sexuality/orgasm to generate and regenerate the energy required to exist within and as these systems like your 'identity'. So I would more look at the question: 'how has pain become something that's part of your identity?' And I'd have a look at how are you torturing yourself, deliberately making yourself hurt? How has this become a habit, to incite as much pain as you can inside yourself? And how/why are you seeing pain as a solution to things? 

Have a look at where you've learned this point, of resorting to pain/torture/punishment as a solution or response to situations. Because this is something you've learned as a childhood-response, copied from your environment, where pain was resorted to as a lack of knowing what else to do. A lack of understanding reality properly. And so it becomes part of the way parents/families raise their children, to program into their child that: 'if you don't know/understand something, you have to punish yourself'. And so you grow up learning that pain is normal or that pain is the natural response to things. So you want to just look into how you've created that relationship with pain as a result of childhood programming and how it's something you've learned from your environment. Cause this is not really 'who you are', it's just how you were raised.

3. Back pain and lower back pain: With back pain you want to look at backchat. Things/thoughts that go on in the back of your mind. A tendency to work things out/think in the back of your mind a lot. So have a look at 'chatter in the back of your mind'. Thoughts that you participate in, like internal conversations, in the background. And it looks specifically related to 'working out problems', trying to figure/work things out. So have a look at what goes on in the back of your mind, and how much thinking/internal conversations you are allowing to take place there, cause it's those internal conversations that will manifest a lot of the back pain you're experiencing. 

So this is the gist of the points you've been experiencing, and what you can start looking into and working on. I hope this gave you some perspective on yourself and your relationship with your pains.