I have a 2004 Chevrolet Silverado 1500 extended cab. My rear wheel is squeaking at low speeds, it is high-pitched and squeaks more rapidly as I increase speed. I had someone look at it (not a professional by any means) and they said it looked like the e-brake was sticking. This has been going on for about 4 months, and it is getting worse and louder. It used to stop when I reached about 20 mph but now it goes on until I reach about 40 mph. I am wondering if this could be something more serious, and if I need to take it in soon and get it fixed, or even if it is something simple I could do myself. Any suggestions or recommendations??

-Thanks