I am self taught. Recently I have hit a brick wall in my playing. Most of them time, I just play a song I know, or improvise and just play around.

I don't know what to learn now though. I know my major scale and modes, and the harmonic minor to some degree. I know chords and how to construct them (I am still learning extended chords).
What else should I now learn? Should I learn my melodic minor and harmonic minor scales all over the board?
You need some inspiration. Sounds like you've got a good start on scale and modal theory.

Here are some ways to get out of your musical rut:

Learn some new techniques. Whether it's fingerpickin' or sweep picking some new 'trick' will keep your interest fresh.

Play/learn/listen to some acoustic music. Sometimes I'll get burnt out on playing electric guitar. Rather than stop playing all together, I'll pick up the acoustic and play only acoustic for several days/weeks.

Play/jam with other musicians. Whether they are more or less experienced than you are you'll get a different perspective.

Listen to a different kind of guitar music than you're used to. There are virtuoso players in almost every genre of music: metal, blues, jazz, acoustic, country...have you ever listened to some of those chickin' pickin' telecaster country guys like Brad Paisley? A different kind of music but no less amazing.

Rather than work on licks and riffage, concentrate on writing music. It's a different skill set but will still keep you with a guitar in hand.

I'm always inspired when I see some dude rippin' it up on youtube. I used to think I was a pretty good guitarist til I started seeing some of these guys. It just makes me want to practice and get better.

Just my thoughts.
it might help listening to other aspects of guitar playing that you may not have come across before. i was the same, i ended up playing the same sort of thing all of the time then i began to look into different styles such as fusion and jazz; guitarists such as frank gambale, greg howe, Brett Garsed, Joe Pass and many others. I just hadn't heard anything like this before and looking into it not only increased my knowledge as a guitarist, but as a musician too. if you have already gone about this then just keep finding new ways to challenge yourself and try not to fall into the trap that i did, just practicing the stuff you already know. i was in that habit for a while and i found it hard to progress. Just keep challenging yourself, and keep at it
Ask yourself: do I know what's going on in each of the songs I play - because note names dont tell you a lot? If not, try figuring that out.
"The end result - the music - is all that counts"
felxdcat, that's a pretty good tip actually, thanks!!!

To the other guys, yea I have a huge music taste. I listen to ANYTHING I find that sounds good.

I find though, that there is just a ton of music theory out there to grasp. I am a technical player. I can sweep pick and alternate pick, and love guitar players like Satriani, Gilbert, Howe, Friedman, Johnson, Lane, Firkins etc etc etc. ( I guess though that yea, I should learn to some more genres....cheers! )

But I am just lost in theory. Cadences, time signatures, inversions, chord notation, counterpoint, progressions, modulations, there's just a ton to learn!!!!

Have any of you guys got tips on how to tackle all this? Like what order to look at things, how deep to delve, and what I should really learn!?