I've learned all of the five minor pentatonic positions, but the thing is I can't solo whatsoever, do you have any suggestion how I can come up with awesome solos (maybe from personal experience etc.). What else should I learn to write great solos?
go on youtube.
find backing tracks.
sound like crap.
sound good.
develop feel and uniqueness.
continue to improvise.
form band.
play in bars.
get signed.
get screwed over by management.
become depressed by failure.
return home.
get on youtube.
find backing tracks.
"The man that hath no music in himself, nor is not moved with concord of sweet sounds, is fit for treasons, stratagems, and spoils. The motions of his spirit are dull as night, and his affections dark as Erebus. Let no such man be trusted."

yea thats pretty much it. here's a pretty sweet backing track for some smooth guitar. you have to practice your scales so you can play faster, learn them on on different frets of the guitar,
practice your alternate picking for speed,
a good way to practice is also attempting to play others' solos. david gilmour solos are not very difficult, yet BEAUTIFUL and melodic, good for practice
One thing that helped me when I was in your situation was learning pre-prepared licks of the genre's I like to play from guitar mags and books which gives you ideas that you can use. Also listening to your favourite lead guitar players and getting a feel for there technique by ear or tab, then once you have some ideas try improvising over backing tracks or a looper pedal and create your own backing track because then you can get a feel for chords and progressions that go with the scale you want to practice or improvise with aswell.