I've a swollen lymph node in my neck for some time now, my doc says it's nothing but I'm starting to worry as sometimes I get shoulder and ear pain?

Enlarged lymph. nodes are almost always caused by an infection. It is probably not related to shoulder pain. Ear pain might be occult infection. However, if your doctor says it is nothing, most likely it is just that. If it persists or worsens, consult your doctor again.