Alright, first of all which python version are you using 2.7 or 3.0+? Remember if you are using Python 3.0+ you should install pytorch via pip3 and not pip.
If you go to your Project Inspector (the thing with the file hierarchy on the left), there should be another hierarchy called External Libraries > Binary Skeletons > torch. If this is the case, autocomplete should work correctly.
If not, make sure to connect torch properly to your PyCharm python directory.