Walking around house blood pressure 143/90. when resting 120/70 male 22. is it safe to be high just walking round house slowly?

Sounds safe.: BP is measured while sitting with both feet on floor. Normal under those circumstances is 120/80 and hypertension is when BP is repeatedly >140/90. Blood pressure under other circumstances is highly variable, there are lots of potential sources of error in measurement, and there is no "normal." your BP sounds reasonable.

Check BP at rest: Blood pressure should be checked at rest, not during/after activity, at least not for purposes of making a diagnosis of high blood pressure (hypertension).

Yes: Blood pressure and heart rate increase with physical activity. To check for hypertension b/p should be checked at rest and repeated at different time.