I urge you to try an experiment: note your level of pain, then try exercising despite the pain to put in a good aerobic workout. Then, after your breathing's settled back down, note your after exercise level of pain, as well as your pain levels throughout the rest of the day..
You may (or may not), notice a marked reduction in your pain levels. If that happens, I suspect it's because your exercise may have forced healing circulation into the congested joint regions and/or the activity helped lubricate your joints. Either way, I'd see that result as strong reason to exercise through the pain (which ought to have the added benefit of maintaining or improving your joints' range of motion, while of course boosting your general health, cardiovascular system, and endorphines level).
To me it's disconcerting that you do not notice a marked improvement from heat (and means your condition's outside my range of experience and education).
I run a daycare in my home and have 4 of my own children, so I'm busy all day. I haven't exercised since the joint pain because it really hurts. I am not over weight and I eat well. I have not noticed much difference after heat.
How is your diet and general health? (are you very physically active, at a lean body weight, and eat very healthy food choices?)
Does heat help considerably? (eg. do you feel much better after a hot shower or hot bath?)
Are you coping with any other notable conditions you've not mentioned?
Also, the past month I have had a lot of heart palpitations. My general doctor has me on a heart monitor for a day and said it was normal.