Hi one and all

I am having a little problem. Last night I turned on the wall switch
that activates my ceiling fan / 60 watt light in my daughter's room.
The light bulb popped out with a blue flash. No big deal right? I went
and got another bulb but it didn't work either. I tested it in another
light and it worked fine. I tried a second new bulb and it too did not
work but worked fine elsewhere. Both the light and the fan are
controlled separately with pull chains. There is a single wall switch
that provides power to both. I have been leaving the fan chain in the
off position because one blade broke off a month or so ago. The light
chain was on the on position when I turned on the wall switch.The fan
works fin by the chain and the wall switch.
I had a neighbor test the wiring right up to and including the inside
of the light reciprocal with a voltage tester. Each step of the way
the tester read 110 red for good. Even on the tab where the light bulb
makes contact inside the bulb socket. It turned red when the chain was
on and off when the chain was in the off as well. What gives here? How
can the tab that the bulb touches have power but none of the bulbs
will work?

Thanks for your help everybody! Thanks!
Ehrin