I am not a person who subscribes to the "no pain, no gain" adage. There is a difference between discomfort and PAIN. It think all of us know pain when we feel it. It is the body's way of saying something is wrong.
Of course, RSD screws up the pain signals at times, but still... If it is really hurting (and not just sore and tired) my opinion is to stop. I have had times where I am actually crying from pain. No one will convince me that is doing me good.
Good luck
Mike