I'm not far behind you in both age and arthritis pain. I was getting the same pain in hips and after losing some weight, I found that I was able to walk longer and the pain, although still there, wasn't as bad. This is what worked for me anyway. Best wishes!
It could be so many things...I would see your primary care dr andhave him order some X-rays to start. Could be sciatica, compression injury, disc problem in the spine, arthritis, etc etc. Have you had any tests done yet? In the meantime, rest when you can and try heat or ice (I always prefer heat personally but ice will decrease the pain by numdinv it a bit), Tylenol or advil. But definitely call your doctor if you haven't already. Good luck