Had swollen posterior cervicle lymph node saw doctor due to infection. Its gone and muscles seem to be tense and swollen a tiny bit. Can this becancer?

Should not be cancer. since it disappeared with antibiotic treatment. Neck muscles may hut from muscle tension from stressing out. Follow up with your doctor and have them re-evaluate the neck pain.
Need more info. Probably not, but I would advise you to see your primary care physician to have him/her check you out. Normally a cancerous lymph node does not disappear on its own and surely does not respond to antibiotics.