What would cause hip problems locking/pain at young age? under 30 hip locks painful and feels like popping out of joint?

Examination needed: Multiple causes are possible. You could be complaining of a painful snapping hip (psoas tendon or iliotibial band are common culprits). Internal joint damage is also possible: tears of the labrum or joint cartilage can cause intermittent painful catching. A thorough examination by your pcp or orthopaedic surgeon will likely lead to e answer for your hip.

Hip list: Labral tear avascular necrosis with collapse degenerative arthritis can present in 30's.