So what are you doing to change your golf swing?
My experience with hip and back pain has been bike is good, golf is bad. I had an interesting situation where I found out years ago my left leg was slightly shorter. Easy fix for the bike, but for tennis, golf, basketball, etc., I just went about it without a thought. Started catching up with me in my late 60's to the point where walking pain free was tough, but riding was fine. Once I added a lift to my left shoes, my pain, "for the most part" went away. I'm not saying that is your issue, but if riding is pain free, it is not the bike and you'll need to address the other stuff you do.
My hip pain was also on the outside.
John