Muddy sounds? What do you mean muddy sounds? If you have poor sound...
Blame it on your:-
1) Your equipment tone[Which means your pedal and your amp]. Maybe they are really that bad that everything just sounds... Bad.
2) Your spoilt pick-up. They are apparently picking up more than what they should. Or less.
3) Your lousy right-arm techniques. Did you remember to keep the base of your palm at the bridge of your guitar? If you didn't, feedback will be imminent.
4) To a lesser extend, your pick. Sometimes when you pick your guitar, you might realize you're actually picking a bass guitar instead with all those additional sounds.