I'm glad you are doing better. It could have been a muscle strain. With MS, our muscles can easily be injured without doing much to them. If we over work an already spastic muscle, it could cause a strain/sprain in that muscle. Sometimes we have spasticity and don't realize it. It could be the muscle was already spastic and when you worked out you over used it causing the strain/sprain.

A really odd thing happened last night though. I was laying on my back with a pillow under my left arm to keep it at just the right angle to not cause pain. I fell asleep that way and slept until I woke up at 3am. My left knee was numb but painful to move. When I rolled on my side and moved it a bit the pain went away but the tingling numb feeling has stayed so far all day.

It was so weird that it's just my knee, nothing above or bellow it. Ah the odd things my body does At least I can almost totally straighten and use my arm today I am stretching it but still babying it to try and get it totally better before I try to use it like normal.

Thank you all for your support and advise on this! I'm so relieved it's fixing itself!