Any improvising musician knows how important concentration is. Let's talk about several things that may disturb your focus:
• The other musicians in the band. You don't play with them for enough time to get used to what they do, they surprise you from time to time, you have to listen to them more than you listen to your own ideas.
• The instrument. It's not comfortable enough, you have to fight with it. Or: there are some dead spots where the sound is buzzing or doesn't sustain and you avoid them. Or: the sound is not exactly what you want, you think more about the next effect you should use than about the next phrase of your solo.
• Disrespect towards the audience and yourself. You think: "They can't appreciate my music, I'll just do some fast licks, that's all they want. I'll keep my music for myself".
Being aware of the difficulties that are standing against the communication between you and your audience is the first step to make your act a real musical show. If you've got the gift of music, don't give up! You have the right to become a performing musician.