What can cause swollen lymph nodes or swollen salivary glands?

Many things. Swollen nodes are often a sign of infection. This can be due to allergy, bacteria, or viruses. On some occasions lymphoma or other cancers can cause this problem. At 35 it is more likely to be benign. I would ask my doctor to evaluate.
Lots of things. Swollen lymph nodes may be swollen due to inflammation, infection, lymphoma, cancer, sarcoid or castlemann's disease. Swollen salivary glands are a little harder but may be enlarged due to infection, blocked salivary ducts, inflammation or cancer. I am sure there are other possibilities but off the top of my head these seem to be the most common.