Hi Sir, I am going to gym since a year, and I am experiencing muscle strain every now and then, (I always do a proper warmup and under the guidance of the personal trainer) but still I sometimes get muscle strain or muscle pull. I have experience this 4 or 5th time in 8 months duration. I have thyroid disorder and I am taking thyronorm 100. Is there any relation between muscle pull and thyroid disorder. Is there any way to make muscle more strong enough or something to improve muscles? Do I need to perform any other blood tests? If yes then which one? Thanks in advance.