"Stop playing the same thing then, it's not rocket science
The problem is that you're not actually "playing the guitar"...all you're doing is mindlessly moving your fingers through some pattern you've learned. You need to start thinking about the sound you want to create and like people have said start listening to what comes out. Currently you're only doing a third of what you need to do to improvise which is the physical actions, the listening and thinking are just as important.
The best thing you can do is actually put the guitar away and spend some time rying to improvise over a backing track without it. Listen to the track , think of what sounds will work and what you could play over it, try to hear it in your head then sing it so you know what it'll sound like. When you've got something, then you can try and work it out on the guitar. At the moment the main problem is you don't really know how to improvise and the guitar is just getting in the way."
One of the biggest helps to playing I've ever read. Some may be able to write songs without this method but some need some kind of back flow to help get them going. Truly amazing advice.