For the last 2 weeks my exhaust has been much louder than normal. It is really heard at around 2000 RPM when im putting medium throttle and a normal load.. After 3000 rpm the sound gets higher pitched and i do not notice the exhaust nearly as much.

I was late for a family event so i went a little faster than normal on the highway while driving to my aunts house. When i came off the highway the exhaust was quiet and i barley heard it.. I drove back home after i got done with the family and the next morning i started up the engine again, drove it, when it was warm it started getting loud again.. I dont get it.. Anyone have any idea what could be causing this random exhaust problem??