Does vtach feel different than sinus tachycardia?

Almost definitely: Ventricular tachycardia is a potentially fatal heart rhythm. Most people feel lightheaded and either pass out or come close. Sinus tachycardia is completely normal.

It can : Some patients do not have any symptoms. However, sustained v-tach is likely to cause hemodynamic compromise (your heart cannot supply blood to vital organs) and is a risk factor for sudden cardiac death. There may also be no pulsation with v-tach which you would not be able to tell! if this is a concern, er is a good place to be asap.