My receiver on my Iphone is low how can i increase the volume mind you the volume is at max

Hello,
If the receiver is that low (and the volume level is at max) there may be a hardware issue related to the internal receiver. The piece is replaceable, but must be serviced by Apple or have your iPhone replaced by AT&T (if under warranty).
In some models of iPhones, this was a known issue that would occur through normal wear & tear. An easy way to tell if it is a hardware issue is to pair your iPhone with a bluetooth headset. While keeping the volume level at max, is it louder or the same as the iPhone's built-in receiver?
If it is louder, than chances are pretty good that the internet receiver needs replacing. If not, then you may have a software issue affecting the sound levels. Try rebooting your iPhone as this tends to "fix" a great many issues affecting iPhones. If that doesn't solve it, perform a sync to backup data, next update or restore your iPhone and then perform the test again.