Hi Merchf
actually there are different reasons for soreness and excersise intolerance, therefore they should be treated in a different ways.
here there are several suggestions.
1. If you check that and know that you do not have blood viscosity problems (high viscosity or too high platelets count) you might try massage and warm baths.
2. You may try viamines related to B group.They usually do well at neuralgias, but they might improve also those pains sometimes. For me it was quite helpful.
3. Check if you have (or have not) any circulatory problems - then the meds inproving limb blood supply could be helpful (as well as massage)
4. Relaxation methods or antianxiety meds, because often sore muscles are just overtensed ones, due to anxiety, which is our frequent companion ;(
no, trembling, especially after several squats in a row is not a weakness, it just means your muscles are less tolerable to the load, but not weak in a clinical means.
Condition when someone feels worse without moving legs is known as 'restless leg syndrome' and usually it becomes very prominent when the person affected goes to bed. A frined of mine has to imitate bycicle riding sometimes othervise he just could not relax his calves and could not sleep. It is also frequent part of BFS.
I personally can tell that today even early in the morning my shoulders were so sore that it was a pain to hold a fork. And I realise now that I had that upper arms soreness and easy fatigue condition far before I got a BFS onset... I just thought it is normal!!!! probably from childhood... it was so easy for me to get pain in my sholder with very little load like toothbrush holding etc... however I still was able to do any work and use my hands and never thought it is any specific condition... and only now I become to realize that it might be certain HMS-related feature.. But I am 42 already and still moving around and typing for 12 hours per day

So I would like to say muscle soreness is very annoying but generally harmless.
have a good day
regards
Yulia