Is your heart "pounding" ALL the time? When did this begin? What is your actual heart rate (pulse)?
Is your bp REALLY 90/140 or 140/90? Perhaps they write it different where you live? 140/90 is high for someone your age, but as with just about everything else, we are all so different, for all I know this could be "normal" for you.............although persoanlly I doubt it.
This bp would not surprise me for someone your age having an anxiety or panic attack.
Have you been diagnosed with anxiety? Has your bp been monitored?
I can't tell you to ignore this nor can I tell you it's due to anxiety............you should see your doctor to rule out any organic problems and if your heart is sound, which it no doubt is, then you may be left with the dx of anxiety for which you should begin looking into treatment for. A combination of a mild antianxiety med and therapy is a good starting point.
I wish you the best.
Peace
Greenlydia