If I strum harder on my guitar a buzzing noise comes out of the amp. Also every sound I try on the amp sounds very twangy and painful to the ears. I use an overdrive pedal with it, but every setting is just very twangy. I dont know if it is the amps problem but it is very frustrating because I can never get the sound I want.

If you don't want distortion, get rid of the overdrive pedal... Twangy USUALLY comes from the GUITAR and NOT the amp... test it on a different amp to decide... Buzzing CAN be caused by "fret buzz" which is due to IMPROPER guitar setup such as neck bend and string height.
Start using ONLY clean channel on the amp and NO reverb. If you verify that the guitar sounds bad on a different amp, take it in to have it setup properly.

Your action is too low for that particular neck. The neck may have a little curve to it allowing the higher frets to interfere with the lower ones. If you strum harder, the action needs to be slightly higher. If your shred and pick lightly, it could be lower.