Does anyone else only have difficulty with beginning to speak?

Does anyone else only have difficulty with beginning to speak? A little background. I used to stutter very badly when I was young, but it went away when I was about 6-7 years old. However, later in life, perhaps in my late teens, I developed a difficulty in beginning to speak. Occasionally, I will not be able to say the first word I want to say. I can almost feel the word, but it won't come out. If I try to force it, I stammer. But, once the first word is out, I can go on speaking, sentence after sentence, completely fluid. This difficulty in beginning to speak only takes place after I haven't said anything for a while. If I am in a conversation, I can go back and forth with another person just fine. I notice it a lot in school when I start to ask a question. Sometimes I find that the word I want to start my sentence just isn't coming out, but another word comes out easily. I'll sometimes start the sentence slightly different than I had originally wanted, just to avoid taking too long to give a response. I don't know if I would call this a stutter, because I will only stammer if I try to force the word out. Usually I can just wait a few seconds and start the sentence fine, or just start the sentence with a different word. People don't notice this about me, since everything is taking place in my head. Is there a word for what I have?