I've also had both hips replaced, the first at age 37, the second one at 40. When you say it starts near the hip, where exactly is that? If it's in the groin area, that's your hip joint. if it's anywhere else - sides or back, for example - it's not the hip joint itself but nerve or muscle related.
After my first hip replacement, despite the surgeon's best efforts my operated leg was 1-1/2" longer than the other. They evened out after my second replacement, but for those three years I had major issues with my lower back, my knees, ankles, even my feet because the difference threw off my gait, the way I stood, sat, etc. It could be that your adjacent joints haven't "gotten on board" with your new hips.
Also, before my hips were replaced I'd get terrible sciatic nerve pain, which resulted in those shooting pains down my legs.
You might do some research into what implants were used in your left hip. The cup of my left one wore out years before it was supposed to (like you, my right hip is perfect) and I had to have it replaced. I could never pin it down, but I suspect it was part of a bad batch that was recalled several years ago.
I've had several friends who swear by chiropractic treatment. If you believe in that sort of thing, maybe a good chiropractor could get everything back in line where it should be.
It's really important that you keep up with some kind of strengthening exercise with your hips - range of motion exercises, simple leg lifts with a 1 or 2 lb ankle weight, also core strengthening exercises to support your lower back. Be conscious of how you walk, sit, stand - I tend to let my left foot turn in if I'm not paying attention.
Definitely get a second opinion - I don't think you should be in this much pain 3 years after surgery. Good luck!
I haven't had a hip replacement, but i do have shooting pain go through my legs, and my knees and hip....I have trouble walking at times but I seem too keep going...I would go back and see your doctor and see what he/she would recommend...Please let me know in how you make out..