Sound not working for adroid phone switched over to straight talk.

hey guys, have a quick question. I have an HTC Inspire 4G, I recently got straight talk switched over so that I may use the phone with it. At first, when the APN settings were set, I was only able to use my phone and text. No mms, or internet. From there, i messed with the apn settings once again, using straighttalks information, and now i have internet, phone, text and mms, but no sound will come from the phone. i checked the phone settings and its where i want it to be, but still no sound. Any help?