What is the difference between 店 and 馆? In class I remember my 老师 said there is a difference between 店 and 馆。
For example: 咖啡店 and 咖啡馆。In this context what is the difference?
There is difference between 店 and 馆. Actually, it is likely be the convention of Chinese expression.

茶馆: a place where you can drink tea.

茶店: a place where you can buy tea, usually called 茶叶店.

咖啡馆=咖啡店，旅馆=旅店，理发馆=理发店

but 饭馆≠饭店，酒馆≠酒店