Suggest Remedy For Throbbing Pain Above Knee During Cold Weather

hi i get a pain in my left leg 3 inches above my knee on the outside area in an area of 3inch radios it feels like the pain is deep it feels like a deep slow throbbing pain . it is worse at night .,and worse when the weathers cold the only time it eases a bit is when i place a hot water bottle over the area of the pain. do you have any ideas please. thanks Paul