Is it possible to fall in love while in pain?

Hi there, maybe someone can show me a different way to look at this.

Ok, so I am a 30yo male with hypermobility syndrome. I have never been in love, but I have a girlfriend who by all rights I should love (but I don't think I do).

Pain wise, a long story short, I hurt all the time from most of my joints/muscles. I also sleep very poorly from the pain/discomfort to the point of serious exhaustion. That being said, I am still fairly active, I just ignore the pain and am careful of what I am doing. Anytime at rest, I am holding myself in the least painful position, or stretching to avoid pain later on.

So now the love part.... I have been with my girlfriend for the last 9mo. We get along very well, and there is no doubt that we are quite compatible in many ways. She very clearly loves me but I've not been able to tell her I love her, because I don't really feel it. And I am not sure I ever will, with anyone.

So now back to my question: Is it possible to fall in love while being like this? I would guess love happens when you feel pleasure often enough with someone that your brain associates them with those positive feelings. Thing is, I don't get much pleasure from anything. Even if we are doing something nice, like cuddling, I still hurt more because I need to move/stretch all the time. So I wonder if my brain is saying that I am not happy because I hurt more. Anytime I am with her (or anyone) I will be in more pain than alone. Logically, I will gladly put up with a bit more pain for the person, but no one said love is logical.

So what do you think? Am I missing something? Or is it caused by something else? As with any relationship there are other tensions, but I don't think they are a cause. I am not an overly emotional person either so maybe I'm just too cold hearted for love. Either way I don't feel it's right to ask her to stay with someone who can't love her back....

Thanks for any input.
James.