I'm aware things like lyme disease can cause tmj. what other conditions can cause it?

Bad bite: Generally a premature contact on 1 or more teeth.

Many: Many conditions can cause TMJ problems like malocclusion , truma to face and chin , abnormal sleep posture, etc. Also some other diffecincy can cause deteriorated disc that leads to TMJ

List: Causes of TMJ syndrome are not completely understood.. Causes may include, misalignment (malocclusion) of or trauma to the teeth or jaw, teeth grinding (bruxism),, poor posture, stress or anxiety, arthritis or other inflammatory musculoskeletal disorders, excessive gum chewing. Treatment can be complex and beyond the scope of this answer. See a TMJ expert for guidance.