Whenever I sit continous for a long time then I get numbness tingling in my arms legs and stifness tightness in head or face. Plz please tell what to do?

Walk around. You should try walking around every 30 minutes or so to get your blood flowing. Try not to stay seated continuously for a long period of time, try stretching your legs out and moving your arms if you aren't able to get out of your chair.