Muscle test?

Well that is a tough one. You know how you feel. If your feeling weaker you might be getting weaker. As for how much it is affecting the rest of your life is a larger picture. You might want to try to do a little more then what you are doing. I'm not saying you should run a marathon, nor swim laps. But if you do not use muscles you will lose them. I know it is hard to do when you hurt all the time, But I force myself to walk everyday. An I try to push a few extra steps in. I do this everyday that I can wake up, regardless of how I feel. Yes sometimes I do not want to, and my eyes may leak, but it is what i feel I need to do.
As for what tests they might do , or can do, small strength tests. Lifting, squeezing, an some fitness tests. I would not recommend a full stress test. They will put you on a treadmill, for as much as you can take. I know medical tests are expensive, sometimes they are needed. I hope for you the best.

Ak angel,

There is the functional capacity test performed at some physical therapy offices. I believe it costs a few hundred dollars but if it's important for you to know for example if you need to know for work or for getting disability it's a very good idea.

Good luck.