Ideas often come from concepts i.e. play this scale over that chord or play alternate chord changes when soloing.
and combining scales, arpeggios, chromatics.
It's not just pulling things out of the air but finding ideas in these concepts.
That's where many ideas originate from with many players.
Music imitates language in this way. We learn a new vocabulary word and see an example of it being used.
Over time we incorporate that new word into our conversation.
Soloing is very much like building a vocabulary of musical ideas to play from.
After awhile it becomes the way we hear and create.
Also, I have found scale patterns and intervals very useful to unlock ideas because, melodies are made of rhythmic, melodic and harmonic patterns.
It's all about incorporating all of this into one stream of flowing ideas.