Lower diastolic after exercise

I am a 26 male and have had some higher blood pressure readings (150s over 90). I am relatively fit and have not had health problems before. I consistently feel a dull ache in my left side like there is pressure building up in there. I have more discomfort and difficulty breathing when laying on my back. As I am typing this I suddenly hear a ringing in my left ear. I have been exercising to get the blood pressure down. It has been mild exercise because I don't feel able to handle a lot. Also, I have been taking beta blocker propanolol to lower the BP. When exercising I have a hard time getting my pulse above 120, even though I used to get above 150 a few months ago. I push myself the same as I used to but for some reason my pulse does not go above 120. The other weird thing is 30 minutes after workout I have consistently had diastolic readings 25 mm lower and pulse up about 15 to 20 points. The systolic stays pretty similar, dropping maybe 0-7mm. Any ideas?

[kenkeith]

A beta blocker will prevent the heart rate from arrhythmia, and as a consequence, there is a limit on heart rate with exercise. One can not with much relaibility take into account readings of heart rate and blood pressure. There is relevant links on your subject of interest. http://www.medhelp.org/tags/show/2316/diastolic