Saying nothing when I should

I have nothing to say but I felt that I should say something, but there is nothing to say so I shall say nothing "Nothing". I have this problem, I know I should say something but I don't say anything. Most of the time I wish I did because I find myself kicking myself for saying nothing. I always say the next time this happens I will say something but what if it never happens again, more kicking. I should have something to say, I should say something. I always have something to think but I never can put it into words. Why? I really have nothing to say on the matter. Kick, kick, KICK!!!