140/90 is the limit for hypertension. I'd have it measured again. No coffee or other stims, no stress, lie down for 5 minutes before taking it, make sure they use the big cuff (most top out at around 14-15" and will show false high values if your arm is bigger) and that the cuff is level with your heart. And it's usually higher when measured by a doctor. ("White coat hypertension") Relax.
If measured properly, I wouldn't be surprised if it's normal.
How much do you exercise now? As BBB said, don't push it to the extreme and lifting will probably lower your resting blood pressure and make you live longer.
@BBB: Do you know why people sometimes feel dizzy, like they're gonna pass out, during overhead presses?