Can a tension headache last for seven months straight and have some migraine symptoms? it is also located in the back left side of my head and my vision over the last year has gotten much worse. I ve had an MRI, echocardiogram, renal ultrasound and blood tests to try and find out what s wrong but everything has turned out normal. The MRI took place two months after the headache started, but is it possible that something in my brain could have become more visible since then?