Guitar Help Please?

I've had the Boss MT-2 (Metal Zone) pedal for a while and it makes so much feedback when im not playing or if there is a break in a riff. Is it suppose to make that much noisy feedback or am I doing something wrong? Should I get a noise gate? If so, can you recomend a good one for the least loss of tone, because I play metal and use a lot of pinch harmonics and things like that. Thanks in advance.