Ok first of all I would like to apologize if this is a noob question but I have to ask it.
I will try to explain it as good as i can , please forgive my somewhat simple explanation .

I've got an ESP LTD KH 602 with EMG 81/60 combo and a somewhat crappy practice amp. When hitting some notes , their ,, counterparts " resonate ( I think ) , thus the pick-ups catching that vibration and so the note is heard in the amplifier with another faint sound behind it , thus producing a dissonance . It's noticeable when the sound is distorted .
Is that normal ? What do I have to do to eliminate this ? Is it because of the guitar , because of the amplifier?
I hope you understand . If not , please ask and I will try to explain .

Thank you and once again sorry if my question is kind of noobish.
It's probably just a case of muting the strings you're not playing so they dont ring out... Without muting while on distortion, you're gonna get all kinds of messy sounds you dont want.
It's gonna be even more noticeable since you have those super hot pickups in your guitar too..