Should I Get a Second Opinion?

I have been having pain for the past six months. Stiffness and pain in my hands and wrists, especially, and pain in my toes, bottom of my feet, and sometimes my heel. My fingers become swollen if I type for too long (I'm a freelance writer) and my knuckles will turn pinkish when sore.

Currently, I'm in physical therapy because I have tendonitis in my right rotator cuff. I'm starting to get the same symptoms in my left shoulder, as well. (I didn't injure it- doctor thinks it's because of bad posture while working at the laptop.) I have crepitis in all of my joints, pretty bad TMJ, and minor soreness/ stiffness in my hips and elbows.

When I went to see my GP, he took a look at my hands, announced they would look worse if I had RA, and dismissed me. I went back and insisted on bloodwork; he relented, but everything came back negative. He has put be on a gluten free diet, even though bloodwork and a previous colonscopy exam came back negative for celiac. (I am lactose intolerant.) I was diagnosed with Raynauds as a teen, and still have cold feet most of the time. I have ulnar nerve issues, carpal tunnel, and numbness in my feet.

Swelling in the joints is pretty minor- sometimes I can tell, but mostly, there's pain and a little bit of redness.

Sticking to gluten free is difficult, and I don't have any irritable bowel troubles if I abstain from dairy. No weight loss or vitamin deficiencies, either.

My GP really doesn't believe it's RA. The pain will abate for a few days at a time, and I will believe I was completely overreacting, but then it seems to flare up. Today, for instance, I am achy all over and my knuckles are red and everything feels stiff. I am on Advil but still in pain. Should I just wait and see what happens with the gluten-free diet, or should I seek a second opinion? Any other ideas about what could be going on?

Thank you so much for taking the time to read this.