Hello. Thank you for coming to JustAnswer with your question, and welcome.
There are many structures in and around the hip joint that can become injured or inflamed just from overuse. I am assuming you did not injure yourself, or are not aware of doing so. For proper diagnosis and treatment, you really do need to see your doctor. It could be bursitis, a tendon or ligament injury, injury to the muscles surrounding the hip, or a problem with the joint itself.
You are already taking the highest dose of ibuprofen, so if this does not help at all, its time to see your doctor.
Once you are properly diagnosed, your doctor may be able to prescribe pain medications that are more effective, and/or prescribe a treatment that will facilitate healing.