Hi I have had dull pain on the left hand side at the back of my head it started as neck pain and it has been 2 days could it be a tension headache?

Other possibilities. By and large tension headaches are defined as headaches which extend about the WHOLE headaches while other types of headaches such as migraines typically show up only on 1 side. Other possibilities such as cervical column osteoarthritis can radiate upward into the head at times. If you'd like to chat 1-1 about this please set up an appointment with me at: www.healthtap.com/drsaghafi.