scales

im just trying to understand better the purpose of scales and im a bit confused. this theory stuff is too much like maths and i'm pretty sure i failed in that subject.

Well, to start with, your question is much too big. It's going to be extremely hard to answer without writing entire books. I'm going to give you a few short answers and hope they at least give you a start.

I would strongly recommend going through the articles in the Theory section here at Guitar Noise. They are excellent and designed to take a beginner through the early stages of understanding the basics of music theory.

There is hardly any math in music theory besides simple counting. You need to be able to count up to 7. Knowing Roman numerals helps too.
scales are used to help create solos right or pick them out when listening to a song?

The "scale" is the set of notes used to construct the melody and/or harmony of a song, including solos. For example, most songs in the key of C major will use the notes of the C major scale (c d e f g a b c). Most will use some or all of the chords of the "harmonized" C major scale (C major, D minor, E minor, F major, G major or G7, A minor).
so if i wrote a song and had some chords down how does one go about creating a solo using a certain scale pattern?
There are many many ways. Probably the best way would be to start from the scale that included most of the notes of the chords you used. For example, if the song uses G, Em and D7, it's probably in G major and the most important notes will be the notes of the G major scale. They will at least sound correct, if not necessarily inspired.
when solos are created does the composer generally only pick from the notes in the scale?

Some do, some don't. Outside notes add extra flavour and dissonance which may make the melody more distinctive and unusual, which often helps make it memorable. Too many outside notes and it will just sound wrong.
how do i know from which scale i should draws notes from?

Well, staying in key is usually best unless you're an expert. There are many articles here in determining key. Minor scales are trickier than major keys and typically include more "outside" notes. I.e. if you're in a major key, there's only one major scale with perhaps the occasional flat-7 or sharp-4 included for flavour. Minor keys typically mix and match the natural, harmonic and melodic minor scales and even Dorian and Phrygian.
what happens if i move say the C scale down a couple of frets, im just playing it in a different key right?

Yes, you're then playing in a key two halftones lower (Bb).