Have you had a fall? The reason I ask is because a crack (even a hairline fracture) in your pelvis will give those symptoms.

Kidney stones will cause similar pain, but pain from a stone is usually agonizing. Have you noticed any blood in your urine? Have you been checked for a urinary tract infection?

What about adhesions? Have you had any surgery on that side of your body? Do you still have your appendix?

If you're male, do you have a varicocele, orchitis, epididymitis or a twisted testicle?

If you're female, could it be Pelvic Inflammatory Disease (PID), or Endometriosis?

Hip problems can present as groin pain, and it's possible for it to be referred into the lower abdomen. My SIL recently had a hip replacement, and almost all of her pre-operative pain was just like you described.

I've had tendonitis of one hip for several months, and although I do get a lot of outer hip pain with it, I also get groin, thigh and low abdo pain on that side.

Do you have any bowel symptoms? Irritable Bowel Disease, Crohn's Disease, Diverticulitis, and Ulcerative Colitis can cause the pain you describe.

Naturally it may not be any of the above, but these are just a few other suggestions for you to consider.