I get an intense pain like this but it's the inside and outer side of my hip/ pelvic area... This is caused by pains from a combination of lower back pain, my pelvic bone being tilted, and muscle spasms. It also gets so intense that I curl up and cry... I use a heating pad, and I have lidoderm patches my Dr prescribed, I will put the patch on the outside of my hip where the center of the pain is radiating from. This helps to numb my skin and also seems to radiate inwards (which I doubt is really possible since it is topical, but once my skin is desensitized it seems to help) and I will lay with the heat and I usually can get it to calm down just enough to be able to sleep it off or at least change positions.... Since yours is on the inside of the hip and groin area, I would also strongly suggest heat like 1sweed did. You may also want to talk to your Dr about maybe a numbing cream? To rub around the area to help desensitize the skin which may help.... I also like to try and stretch the area out (I do daily stretching a few times a day to help...) I know it hurts, but you want to make sure you're moving around enough, and also it may help too open the muscles up a bit, but do this after heating for a bit.