I have cervical kyphosis and over the past few days i've developed multiple joint pain in my left shoulder elbow and wrist. are the 2 connected?

Not likely: You have ehlers dances syndrome were you have hyperbole joints leading to early joint arthritis from the loose joint motions beyond what is normal.

Musculoskeletal: Systemic conditions affecting the musculoskeletal system come to mind. Rheumatoid arthritis affects multiple joints, including spinal facet joints, shoulder and elbow/wrist/hand. Connective tissue laxity in ehlers danlos may be the contributing factor for these as well, your orthopedic provider may be a good resource for this.