My well switch (I think) keeps clicking on and off. When I run the water there is a surge, back and forth... sometimes the pressure is low.

What type of tank do you have and how large is it?
What does the pressure gauge read?

Not sure what type of tank it is. It looks like about the size of two bbq propane tanks. I looked for the number of gallons... could not find anything. It is probably about two and a half feet high. There are two gauges. One says 48 the other says 40. When there is a click, the one that is 40 jumps up to 50 then goes back down.

Is it painted or is a galvanized tank? Is there a air valve on top, like on your auto tire?

It"s painted & yes it does

So tell us what your problem is Papa Will

Papa Will, are you the original poster from 1-1/2 years ago? Or is this a new problem?
If so, what is the problem?