If you have crohn's, there's a good chance that you're developing the arthritis associated with it. IBD-arthritis, I believe, is more likely to affect the larger joints, like hips and shoulders, and certainly lower back (sacroilial joints). If it continues, you might consider seeing a rheumatologist. Most GI doctors I've seen completely minimize joint issues. Also, with your IBD, you may not want to take naprosyn; a rheumy can give you something that would be much safer with the crohn's.
As a fellow hip pain sufferer, I can sympathize with you. I've lived with hip pain for the past 2 years.
Hope you feel better soon,
Current dx: Rheumatoid Arthritis
Suspected dx: UCTD/Early Lupus
Current Meds: Enbrel, Plaquenil, Aciphex, Ultracet, Zyrtec, Allavert-D, Zantac, Tylenol PM
Past Meds: Relafen, Vioxx, Mobic, Voltaren, Sulfasalazine, Entocort, Prednisone, Humira, Reglan