Suggest Remedy For The Pain Due To Sprained Hip

i sprained my hip about 3 weeks ago, i went to a sprots doctor and he told me tht, and to rest for a week, i did, iced it, streched it. and in a week i started running again (training for Marines), but the pain returnes at about a mile and a half into it, its not there soon after i stop running, and throu out the day, is this normal, if so what should i do to get rid of the pain, or what does this sound like? i really need help, my career could depend on it