I like to think that I 'think outside the box' when it comes to guitar playing and composition. My advice is to forget about scales and modes etc - if I start thinking that way my creativity goes out the window and I get boxed into shapes and rules etc. I always listen to the backing music and imagine the solo I want to play, sometimes it helps to sing the solo parts, then work them out section by section. It's just too hard to jam out an amazing solo - you end up playing the same runs and shapes all of the time and it can be really hard to come up with something thematic that actually goes somewhere. That's what works for me anyway. I never think about scales and to be honest I don't know much about theory but I I know the fretboard backwards and what works where and with what. Jamming can be fun and you can come up with some great ideas off the cuff, but I like to spend time creating a solo as an independent composition with a beginning, middle and end and I find I can only do that well if I put the guitar down and let my mind create the music before I put my fingers on the fretboard. The way I look at it is, the mind is a far better musician than the hands can ever be. Anyway, this works for me, other will advise learning theory and that may very work for you too - if it works for you then continue doing it - if you get stuck in a rut try changing your approach.