When I drive I get a pain in my right groin at the very top of my leg, the pain is burning and only goes away if I stop and get out the car and walk, ?
See your MD. Groin pain is frequently associated with hip dysfunction. It's not the only possibility but the burning could also be a symptom of meralgia paresthetica from compression of the lateral femoral cutaneous nerve by your belt or pants which is relieved when you stand and walk stretching out the nerve. Your md can help evaluate this and find an answer.
Missing info. You do not say how old you are, but the burning quality is associated with neurogenic pain, and a subtle disc herniation, incomplete, can do what you describe. Sitting makes them worse. I'd recommend you to a neurologist to examine your reflexes and listen to your story before "reflexive" imaging.
Nerve pressure. You might be putting pressure on the anterior femoral cutaneous nerve. Make sure a belt isn't pressing on the brim of your pelvis.