I hate to sound negative....but, as an electrician, you may be opening a can of worms so to speak. I did a job for a friend recently where I had to remove 2 "knob and tube circuits from the electrical panel". No biggie, turned the circuits off and traced things and turned out to be only 2 small rooms with some lighting. Rewired those two rooms, change the whole panel, turn breakers on, and find out some other rooms not working.
Reason is some hack job electricians tapped off of the "knob and tube" neutral wires to feed other circuits. So in essence you had a neutral helping different circuits than the Hot wire. Also a 14/3 wire feeding a split receptacle in kitchen had issues too. 2 hot wires coming in on the same phase so you would think 2 different circuits on that receptacle but nope. Somewhere in the wall the 2 wires were connected, so you could turn off one breaker and the whole plug was still live...reason is because both circuits were on a Tandem breaker on the same phase so it would never trip. Turned out I had to rewire almost the whole house lol, nightmare job. Also found 4 covered/drywalled junctions in the basement lol. So instead of a one day job it turned into 4 days worth of work. I try to stay away from old residential jobs....too many hacks and home depot/self help electricians out there.
I am assuming from your issue you have too many outlets on one breaker including the microwave, thus tripping the breaker due to overloading.
The only way this may be remedied inside the panel is if, there are 2 wires tied into the same breaker and you have spare room to add another breaker. Then you can take one wire off and trace exactly what it is feeding. Then maybe, you can install that wire on a different breaker.
Word of advice, if someone offers to just install a 20amp breaker on that one circuit to increase the amperage before tripping, then kick them out of your house lol. Most likely you have 14 gauge wire and that's a no no.
You are probably looking at anywhere between 500$ and 2000$ depending on the severity and probably two guys to pull wire, drill holes through the attic. Might also be at least $50/hour not including material. You may also need to make holes everywhere in drywall in order to pull new circuits, so add the cost of patching and painting (which you can probably do yourself).
Also, any new work that will be done will need to be up to electrical code......and it doesn't sound like it is up to code now.
Hope this helps