Is there any different between these two type of movies? I believe there are differences.
Romantic movie is where you will fell the need to stay quiet the whole movie, get the feeling of love sweeping over you and you can relate to what happened to the hero and heroine on screen. There are tragedy, there are trials and tribulations. There are protagonist and antagonist. There are plots, sub-plots and twist enough for you to dance with. They are also known to be from literature. Think The English Patient (my favorite). Sense and Sensibility. Emma et. al.
As for chick flick, it is a new genre. Ever since there were chick lit, which are people writing on a lark and in an easygoing manner. Where their writings border between literature and pop-culture. Where they still sell their books in millions and celebrated as the new "Jane Austen". Where these books are then made into movies. Some are straightforward. Some are "based upon".
Some are just movies but the ideas came from these type of books. These can be seen in The Proposal. The Ghost of Girlfriends Past (Dickens turning in his grave). 10 Things I Hate about You (Shakespeare anyone?). Oh, it seems that these chick flick also has the ideas coming from books. But with a twist.
To me, nowadays, you can't really differentiate movies that fall as a romantic movie or a chick flick base on which medium it is adapted from. Some are movies which are just there as fillers although there are big names headlining them. Some are real movie which makes people think.
Give me the latter anyday of the week. But, that is just me.