What Causes Severe Headache?

My grandmother is 83 years old. Last Sunday she felt a sudden pop over her right eye followed by a severe throbbing headache which has lasted for almost a week now. She said the pain is worse when she walks and she said with each step she takes it feels like her head "just jars." She has type 2 diabetes, high blood pressure (controlled with medication), hx of heart disease, and recent cataracts surgery on the right eye. She has had a CT Brain wo contrast, which came back normal, and an MRI Brain wo contrast. We are waiting to hear back on those results however I don't feel like there is a bleed otherwise she would have been ruled a critical value based on the Diffusion sequence. She has only had 1 other headache in her lifetime, so this is very rare for her to have one especially to last a week. Because of her diabetes, she was told that she had bleeding behind both eyes. Is it possible that this could be a vascular issue causing this headache, and should we request an MRA Brain? Also, what other conditions could be causing these symptoms?