Thing is, Pakistan doesn't really support terrorism. The military however keeps close ties with militant groups largely to keep them in check and to leverage them in case of an all out war. In fact Pakistan had a massive campaign to rid itself of terrorism after a terrorist attack on a school. So no, Pakistan doesn't support terrorism, that's just propaganda spread by one of our neighbors unfortunately.

For cross border issues, Afghanistan and India have internal issues (as does Pakistan) but they both look to blame Pakistan for their own short comings.