I've recently noticed a lump on the back left side of my head... it is tender and slightly sensitive to the touch. My feeling is that is an inflamed occipital lymph node, though I don't appear to have any scalp infection. My lymph nodes in my neck are also inflamed (both sides). I have also had some pains in my left side, just under my rib cage. I don't feel ill, but i haven't had a lot of sleep (a little over 6 per night) and have been working ling days. Please advise me as to what this could be and what i should do.