I would recommend 2 people.
1) Start with getting your bike fit correctly. There are a number of bike fitters in the area, but I would recommend Eddie at 55 Nine as he's an endurance mountain biker. He will fit you on your actual mountain bike and offer you pedaling mechanics advice for your mountain bike. Expensive, yes, but totally worth it.
Once you do that, you'll still need some work done to fix your knots/tissues/etc.
2) Go see your doctor of choice, or Dr. Sadri from 1st Choice Healthcare. I was recommended there by a Crossfit friend and they worked well for me and helped me out.
Going to see a doc without getting a pro bike fit will just fix your problem until you get back on the bike. Don't do one without the other