Probably, pip installs packages into dist-packages directory, which is not included into PYTHONPATH environment variable. You have a couple of solutions:
1. Create and configure virtualenv for your project, before using pip. This is the most Pythonic way
2. Try to install Django using built-in pip module:
python -m pip install django
This command should install packages into site-packages directory.
3. You may also add dist-packages to your PYTHONPATH