Mr.Saif Ullah Bhatti, it is hard for you to apply for a tourist visa to China. In pakistan, the tourist visa is issued to aliens who come to China for family visit or tourism, if your purpose of coming to China for visiting friends, you can't provide the Certificate of the relationship between you and the person in China you want to visit (original and photocopy)

For tourism, Pakistani citizens should first contact a qualified travel agency of China and settled down all the details of the tour. And then the tourist agency may arrange a visa notice form for a travel group (more than 5 people) and a group-visa for you. At present, individual tourists are not accepted.

Therefore, the only option is you join a tour. You can go to the embassy to enquire what documents are required if you go to China just for visiting Chinese friend.