I haven't experienced any pain while exercising, but I have found it very difficult on account of my muscles not being strong enough to support my body as I try to move it fast! I know it's not the same thing, so I don't know if what I have to say is helpful but I'll say it anyways (you never know)
Would things like flexibility training (stretching) and strength training (strong muscles to support your bones) help at all? Exercises like swimming or aquafit if you have access to a pool, or low-impact yoga (apparently there is such a thing) if you have access to yoga classes or even a yoga DVD (with which you can go at your own pace!) - maybe that could help?
What type of exercise do you do now? I don't know if you use a machine but if you do use a machine, are there other machines you can use that have less stress-impact on your body but still allow you to work out the way you'd like to?
How about your sleep pattern, your mattress, and your footwear? I feel like that came out of nowhere but now that I've written it, it makes so much sense. And stress level too.
I guess what I would say is take it easy and do what you can as you can do it. Committment is key I think, but there are many ways and things to committ yourself to
Experiment with different exercises, see what makes you feel better, but don't push yourself to the point of hurting yourself. I was talking to someone a while ago who had told me that she started out exercising with just a walk around the block, and she built up from there on and now she's running a bit even!
Okay, so I don't know if any of that is in the least bit applicable, maybe I'm just going on and on
. Either way, I hope you find a way to exercise that leaves you feeling good and strong