Excellent advice from the guys above.

I've never been great with theory but I my playing improved considerably when I stopped trying to improv everything. Try to listen to the backing music and imagine what a great solo would sound like over it. Then just spend time using your ear working it out without relying on repetitive runs and patterns. You will get a completely different type of solo from this approach than if you tried to jam over it. You can you mix it up with a bit of a jam/improv to get a nice semi-structure.
The thing with imagining the solo then working it out is that you would never usually be able to jam something like that out from from scratch, also by imagining what you want to hear you aren't sticking to stock patterns or particular scales. You learn a hell of a lot by working out what you can hear in your head without thinking about shapes or patterns. Just another method worth investigating, it could work for you too.