Water pressure drops in well water home, stops completely for 5-10 minutes, then comes back full pressure
Check the water pressure &amp; air pressure of your system when the water almost stops flowing as you've described (i.e. before the pump engages).  You may have a small hole in your bladder.  The other possibilities are:


The valve that your incompetent service person opened is not opened completely.  That would cause the incoming water to not keep up with the outgoing (shower) water &amp; therefore need some time to recover before it will give you proper water flow. Ensure the water valve is open properly.
Your pressure switch isn't working as designed.  It may not switch on at the proper pressure level.  If it is adjustable, try to adjust it to the proper turn-on pressure.  If it isn't adjustable, then replace it or have it replaced.
You may have an electrical wire/connector that is intermittently working.