What type of specialist should i seek out if i am trying to find out the cause of repeated frozen joints? i don't have a hx of diabetes, htn. i'm pretty healthy but keep getting frozen shoulders and now my hip is losing rom?

Work up is ideally coordinated by a primary care physician that can refer as needed to either a rheumatologist or Ortho doc depending on findings on exam and initial work up. Physical therapy is usually part of the treatment.

Start with your primary care provider, but from what you described, consulting a rheumatologist would be prudent. Wish you good health!