Every once in awhile the power will just go out in my house. When I go to
the service panel and turn the Main power swith off and then back on it
seems fine again. Sometimes I need to jiggle the main power switch for it to
go back on.

It looks like two sideways mounted light switchs attached together. It is
also sometimes slightly warm in the touch. I have neither added nor
subtracted any appliances or changed their locations it the past 6 months.

This just started happen a few days ago and has never happened before. It
just feels like the main power switch is like a chanky old light switch on
it's last leg. The panel was upgraded to 100 amp 15 years ago.

The question is can I just have an electrician come and change the main
power switch. Can I do it myself? I would prefer not to fool with it, and
does it sound like a relatively inexpensive job? Any other suggestion would
be much appreciated. Thanks.