If I have high blood pressure, do I need any special arrangements for flying?

You need control BP. No matter you are going on plane or not, if you have high blood pressure, you need to control it either by food or medication. High blood pressure will have chronic or acute effect on the body. Once blood pressure under control, you don't need special arrangement for flying.
Usually not. Make sure you take your medication as prescribed by your physician. If your blood pressure has been under good control and you are feeling well there is generally no problem. If you blood pressure has been unstable or very high recently, regardless if you are having headaches or not, you should definitely consult your physician before flying. Flying with uncontrolled high blood is dangerous.