Lithographica -

I'm pregnant, too. An MRI is safe during pregnancy. They may not be able to use contrast. I can't remember if they used contrast for my brain MRI's that were done outside of pregnancy. I've had an MRI in both pregnancies and may need another one.

Chiropractors are like any practitioner. You can find good ones and bad ones. Don't be leery of them but also if you're not comfortable don't go that route. I've seen a chiropractor since 4 days post injury (7 years ago now). He didn't pick up on my TOS. It was a regular MD who finally listened to me, had me do a few tests in the office and then sent me to a physiatrist suspecting my problem was TOS. My TOS was diagnosed 10 months post-injury by a physiatrist (physical rehab medicine doctor). He actually apologized that it took so long for me to get diagnosed given I was the "most classical textbook case of TOS" he'd ever seen. It all matters who you see and sometimes what day you see them - are they having a good day, are they distracted, are they open to TOS, etc.?

For me, the pain wasn't constant. I'd do something that set it off but I couldn't trace the source to any one item. By the time I opted for surgery (10-11 months later), the muscles of my hand had atrophed and fingers curled up. I couldn't grasp anything and the arm/hand was useless. Now, I can use the hand and write, pick up my son, wash dishes, etc. The muscles and nerves have recovered and I'm thankful I opted for surgery. You will have problems taking care of the baby with these symptoms. I've been there and will be there again as I have TOS on the other side due to a cervical rib/shoulder injury.

Distinct pop - Has anyone looked at your shoulder? Shoulder problems can cause TOS like symptoms, too (personal experience with this, too).