Hi. My 11 Year Old Son Has Been Having Severe

Hi. My 11 year old son has been having severe headaches going on a year now. They are not like migraines as in sensitive or light. He had a MRI to see if there was anything going on in his head. The MRI report came back that he had numerous enlarged lymph nodes through his neck area and he had not had an infection lately. He also bruises extremely bad. What do u think this could be?