What causes dull headache that does not shift?

Hello doctor,

Three weeks ago, I had a headache late at night. I managed to sleep, but it was still there in the morning. It was a unilateral headache on the left side of my head. Pain is in my temporal area which sometimes radiates across my cheek and even down my jaw, as well as on the top left of my head. I have occasionally felt discomfort on my chin too, almost like a bruised bone feeling when pressed. The pain subsided with Paracetamol and Ibuprofen but returned the following evening. Medication no longer had any effect on it. After a week of non-stop pain, I went to my doctor. He could not work out why I was having the pain when I have absolutely no other symptoms. I feel fine other than the pain. He sent me to another hospital for further evaluation. My blood was taken and came back normal and I passed all of the doctor's strength, reflex, and cognitive tests. It was a mystery to him too. He referred me to a specialist who said it was likely a benign tension headache and I was discharged. While the pain is not generally as bad as it was, it is still there every day. I get a few moments of pain every now and then, as well as head pressure. But, some days the pain lasts all day, a dull ache that does not seem to shift. The most annoying part is that within a minute of my head hitting the pillow at night severe pain suddenly kicks in my left temporal region and back of the head. I could not sleep without taking medication. At home, I have tried three different pillows, yet I still get pain. The only medication I take for it is a combination of Paracetamol and Aspirin. I am currently taking it each night about 30 minutes before bed to ensure the pain will not kick in. If I do not do this I simply cannot sleep. I do not want to be reliant on these pills or take too many, so I am trying to limit myself to just two of each before bed. I still have no other symptoms other than unilateral pain and pressure. I do not suffer from migraines and do not feel anxious or stressed at the moment. The only anxiety I have recently felt was during hospital visits as my pulse rate went a little high, but returned to normal later. Is it really a tension headache or something else? I must stress that despite days when the pain has subsided; the discomfort has been constant throughout. I am always conscious of it. Please help me out of this. Thank you.