I have two painless lumps in the back of my head at base of skull. started with one small one, then a bigger one right below. should i be concerned?

I would get them che: Painless lumps at the base of the neck could represent a variety of different things including cancer. Generally red swollen and painful lymph nodes might represent infection however painless swellings may be more concerning.

Need to be checked: Any lump could potentially be of significance, be cancerous. You may be dealing with benign (non cancerous) lymphnodes, cysts of the skin, fatty tumors, but also some cancerous lesions. Since these have increased in numbers you need to have your doctor check them out. Painless usually just means that this is not caused by an infectious process.

Need evaluation: Lumps in this area can be infections, fatty tumors, enlarged lymph glands, or sometimes cancerous. Please have your internist check them out.