have a problem/have problems是单复数的差别
have problem一般不做词组用,一般做定语,比如：
What`s wrong with me?You think the problem was just me?Let me tell you,it`s you,you asked so much for me,it`s me who can not stand this,it`s you who have problem
我有什么毛病?你觉得问题全出在我身上?我告诉你,你对我要求太多了,就我才能忍受你,全是你的问题才是.
最后一句的用法