I'd echo the advice to go in and see someone; not just anyone, but someone who specializes in sport medicine
there is a ton of info on the internet for ITBS (it's a common injury among runners-probably hikers too :)), this article suggests a few ways to possibly combat it
Best advice yet re a sports medicine ortho. In addition what can be thought of as an ITBS issue, can often caused by a bulging disk. Have had the same issue. Serious PT therapy solved the problem.