I think i have a pinched nerve in my tailbone. i've been doing yoga and seeing chiropracter to help. do i need an xray or other diagnostic services?

No: If you are having weakness or tingling or numbness in your legs, imaging may be considered. Other red flags would be trouble with bowel or bladder, or fever. If you have not been evaluated by a physician, that might be worthwhile because that could also lead to a referral for a good physical therapist that is comfortable with the pelvis, hips and pelvic floor. That could really be helpful.

Possibly: The chiropractor might offer short term massage relief but no diagnosis or cure. For your condiion see an orthopedic specialist who might order diagnostic studies including x-rays or even an mri.

Stop seeing chiro: There are many things that could be causing your symptoms. If it is not a sore muscle then chiro (massage ) is unlikely to help. Nerve pain, slipped disc, fracture, etc can give you similar symptoms and a chiro rubbing your back wont help u. See you md for a work up. If nothing serious is found you can go back to the chiro -- though if it hasnt helped... why would you ?