I know what you're going through.

I got so sick and tired of playing metallica's song that I didn't progress for some years.

Then I bought some books on lead guitar. Speed mechanics by troy Stetina was a break point for me. Great exercises in there.

After a year of practicing his stuff, I deceided to stop playing scales and other people music and start playing my own stuff. I did tons of riffs I liked and few songs here and there even joined a death metal band. Learn to play with multiple guitar tracks.

I began to develop my own style and sound. about two years ago I started playing more accoustic songs. then a year after that I started fingerpicking. Saw that I wasn't so bad at that and continued.

Now I deceided to work on my bad habits. I inlisted for online lessons with The Jonezter (guitartrick host and guitar war champion) and I'm now working on mistakes I made and stuck with for the past years.

As you can see I took a lot of paths in my quest for musical knowledge. Maybe you're at a point where you need to try something else. I would suggest playing styles you're not used to but that you like.