Can I check the voltage myself with a multimeter? If so how?
Yes. Set the multimeter to read AC Volts, on a scale such as 0 to 300 volts or some such number that will assure it won't be driven past the upper limit of the scale. Make sure that the test leads are connected to the proper jacks on the meter for making an ac voltage measurement on this scale.
WITHOUT TOUCHING THE METAL PROBE PINS AT THE END OF EACH TEST LEAD, insert one lead into one of the two vertical slots on an ac outlet, and the other lead into the other vertical slot. The meter will then indicate the line voltage.
While you are at it, also measure between the shorter vertical slot (which is ac "hot"), and the ac safety ground opening on the outlet (the one that accepts the circular third prong on an ac plug). That should indicate the same voltage as you measured between the hot and neutral terminals.
Then measure between the longer vertical slot (ac neutral) and ac safety ground. That should measure 0 or very close to it.
Then measure between each of the two vertical slots and the screw which holds the faceplate on. You should get the same two readings as when you measured between each of the vertical slots and the ac safety ground prong.
If any of these additional measurements are not correct, it indicates that there is an open connection or a miswire somewhere.
Regards,
-- Al