Upper thigh pain can be caused by several different factors. It may be lower back posture or poor core stability. But is can also be due to foot posture and muscular imbalances. These can all contribute to injuries around the thigh or groin. Sports that involve a lot of kicking, sprinting or changes in direction can lead to injuries by straining these muscles. If you have sustained an injury, wear compression shorts to ease some symptoms. But it's always a good idea to seek an assessment from a Chartered Physiotherapist.