Headache Post Surgery

I am 7 weeks post surgery. Thought I was doing pretty good except every good day is followed by a couple of bad days. Two weeks ago I found out I have blood clots in both legs and both lungs. I have now added blood thinners to my cocktail. Over the weekend I got a headache that want stop. It is different than the ones I used to have. It gets much worse when I try to sit up or lay down. My neck is also stiff and the nausea is back. I had a CT scan and it was ok. Will have an MRI on Friday. Any thoughts on what to expect? Any suggestion?

Thanks for responding. I have been using Arinca cream and ice on my neck. At this point I am doing whatever I can to manage the pain until Friday.