I've read some people experience swollen lymph nodes after receiving the covid vaccine. how common is that and does it occur more frequently with one vaccine or the other (moderna vs. pfizer)? how soon after would it occur and how long to resolve?

Fairly common: Lymph node swelling indicates your body is reacting to the vaccine and is producing antibodies, just like it is supposed to. The swelling is more obvious in very thin people, but happens in most. Usually last 3-5 days and gradually disappears. Since all the vaccines cause you to produce antibodies, happens equally both both types.

Axillary nodes: With Moderna vaccine - 10.2 % developed axillary swelling/ tenderness within 7 days of 1st dose & 14.2 % after 2nd dose. Phase III trial for Pfizer only had unsolicited reports for lymphadenopathy so that data is likely to be significantly minimized. REF: https://www.ajronline.org/doi/pdf/10.2214/AJR.21.25604 * Lymph nodes usually normalize in about 2 weeks - sometimes up to 2 months.