Need Help Please

Hello Andrew, I really need some advice. I am lost I have been playing for about 20 years now, but everything that I know is just cover songs that I had learned from tabs. I really would like to understand what scales go with what. I guess I need to start with the theory so I understand more what I am playing other than just playing it. If you could point me in the right direction I would appreciate it thanks.

Soloing

Hello Kristofer, My name is Aaron I am new member here but I have to say this site is a blessing for me. I have played guitar for about 20 years off and on, I wish i would have stayed more steady with it but I kept getting discouraged because I couldnt find any good teachers, but looks like I finally have. I have just recently started to really get into soloing as where I would be improvising my solos instead of learning them the way a guitar tab would show the artist playing them. I had been looking around your site and I couldnt find a lesson on what scales to use for different chords. What I mean by this is sometimes I try and improvise a solo but somewhere my notes start to sound off and dont go with the chord that is being played. Lets say we are playing blues in A then we would switch to D then back to A then to E I would try to solo using the A pentatonic scale but when the song would switch to D I get lost and cant find where to go from there maybe you could help me clear up this problem. Thanks alot for your time and again this site is awesome all your instructors are very good I look forward to working with all of them.