Do you need to have cancer present in a lymph node to make all of your other lymph nodes enlarged due to cancer? i have 2 pea sized lymph nodes at the back of my head which haven't in 6 months, so can they cause my other nodes to become enlarged?

Repeat question; see previous reply. An inflamed or enlarged node cannot cause another to enlarge and get inflamed. This still sounds normal and nothing to worry about. But see a doctor if you remain concerned.

Unless your lymph nodes are bigger than 1cm, they are benign. You can watch your lymph nodes over 6 months; unless they grow up to double the size of the present size, you do not need to worry because it is normal to have small lymph nodes in our body.

What you described does not suggest any cancer. You may feel the nodes every couple of weeks, if any of the lymph glands doubles in size, becomes painful, ulcerates, or other nodes become enlarged, or you develop fever, or lose weight, you should see a doctor. Wish you good health!