Hi. I am a first time poster here.
So I went to the Doctors today with a pain that I get in my left pelvic area when standing up after sitting down for a long time. I don't really get the pain at any other time, and it is fine when walking/exercising. The pain feels like a stitch sensation. 

I was expecting the problem to muscular, but was really scared after the doctor decided it would be a good idea to have a sample of poop sent away for analysis and some blood tests done. The doctor did give me a number for a physio to contact in case the pain is muscular, but I know I will be really worried now until I get these results through. 
Can anybody reassure me?
Thanks for reading!