nice gear but still muddy

I've been playing less than a year and I've acquired an americam strat, fender blues jr and a tube screamer pedal. I'm struggling to find a good fuzzy or distorted sound that I like. I've tried settings all over the place and anytime I get my major or bar chords sounding like I want, anything I play minor sounds horribly muddy almost out of tune at times. Anything I can try to help figure out my equipment? I honestly think it sounds better without any pedal and using only the jr fat setting. But still not happy with it.