Is surgery the only option for shoulder subluxation?

Depends on activity: Shoulder subluxation or dislocation when recurrent usually requires surgery; however, it depends on the ease or activity that induces the instability. For example, if it occurs with minor activity level and only once or twice a year it may stabilize with time.

No: Actually non operative treatment for shoulder subluxations (instability) is the main stay of treatment. A good physical therapist can likely resolve the problem.