The fusion itself does not become of sufficient strength for one year to 18 months. It is important that exercise is engaged in so that the muscles remain fit. Some approaches use the patient's own bone. The surgery can be done from the front or back. Some approaches may cause certain muscles to die and turn to scar tissue, which does not function normally.
Scarred muscle can continue to hurt, even in the presence of a fusion.
The only time that I prescribe anti-inflammatories before athletics is if the patient has experienced it in the past or has muscle soreness as a result of that participation. Anti-inflammatories will not affect the bulge but may affect the muscle or joint over the segment. The medication is usually taken the evening before the event, the day of the event and then the following day. My daughter was involved in an automobile accident a few years ago and as a result has chronic back problems. That is not unusual.