Does cottage cheese melt like other cheeses?
No. Cottage cheese is a type of acid coagulated cheese, much like ricotta, feta and farmers cheese. It will continue to have lumps when heated, which will never be smooth. 

The other type of cheese to avoid for melting is long aged hard cheeses like Parmesan or sharp cheddars. These tend to "break" and separate into an oily mess. 
Adding butter or cream usually helps, but can dilute the flavor. 
Using starch such as a bechamel sauce as a binder has a similar effect, but using a blend of short aged cheeses like gruyere or jack and stronger flavored cheeses like cheddar is a good option.