[donk.]

@Stacey

The pump should have a minor vibration to it, hard to tell unless you handle them regularly.

If the power matches the nameplate rating, (leg to leg, not to ground) I would suspect the motor is seized, the impeller has disintegrated, the impeller is stuck to the volute.

Depending on your level of DIY, you can turn off the pump, close the supply valve to the pump, plus all zones. Then loosen the 4 Allen key bolts holding motor to the volute. Wiggle the motor off, drain the pressure until it stops, then fully remove it.
At this point you can turn the power on to the motor only, and verify if it actually spins.

Ps, the gauge is faulty, I doubt the heating temp is 260F. It may be possible that the 18psi is actually xpsi
Furthermore, just because there is pressure, does not mean there is flow

I could be wrong on all of the above, this is just what I see based by information provided over the eeeenternets

At this point, I would personally recommend you call out a professional, Incase things don't reseal, or leak, or you need to further diagnose.
4hrs labour, bill should be sub 500$ for a repair assuming no parts need replacing