#1
I was practicing my screaming over loud music in my car, something i had stopped doing because i would try to out-scream the music and make my self louder...it made my voice hoarse and throat hurt, so now i would only practice with one ear bud in my ear, and that really helped out, i was doing good, no pain or hoarseness at all, i was so happy i was making progress..until a day ago, i turned up the radio and sang/screamed along and my throat got really irritated and felt like mucus was building up in my throat, but it turned out to be like a lump, something swollen in my throat, i thought it was mucus but its not, now its just there bothering me, did i screw up my vocals? what can this be?
#2
It could be a vocal fold nodule. You shouldn't be yelling, ever. Singing should be effortless and if you need to yell, you're doing wrong.
Screaming in metal is different though and if you want to do that, you need to learn the correct method.
#3
Singing should not necessarily be effortless but it should always be well controlled.

I'm not sure if there's any problem but for now rest. And don't sing over loud music again without a mic. You can't hear how loud you're yelling...that's how everyone loses their voice at live shows.
#4
^What this fellow said. Don't speak more than you must for at least a week. You'll be fine. Even if it is a node, you caught it early most likely. They are soft, bruise like things at first. They only harden after you ignore their pleas for discontinuing the abuse.

You definitely have some technique issues with your screaming though.