Tension headache

A 30-year-old woman comes to the office due to daily headaches for the past few months. She describes the location to be all the way around her head, and she feels like her head is under a lot of pressure. She rates the pain as a 5 on a 10-point scale, and it often worsens in severity throughout the day. She works as a secretary, and she states that she has been under a lot of stress lately. Her medical history is significant for bacterial sinusitis treated with antibiotics one month ago, and family history is significant for migraines on her mother's side. Temperature is 37.0°C (98.6° F), pulse is 65/min, and blood pressure is 115/75 mm Hg. Physical examination shows mild tenderness on palpation of her posterior neck and occiput. Which of the following is the most likely diagnosis?