It could be a hardware problem, but before concluding on that, let's do some tests.|
1. Try a reboot - it should clear the stuffs that are temporarily down, most of the times.
2. Test the speakers under CIT mode - To enter this mode, go to Settings » About phone » tap multiple times on Kernel version and run the speaker test. See if it works.
If the tests in CIT mode gets passed, it is NOT an hardware issue. You can flash the ROM again or do a factory reset to fix the issue. Only if nothing works, you can get the help of an authorized personnel from a service center. But try these steps first.