Is there such thing as underpaid people? The short answer is No. Each person is getting paid the salary or an hourly rate s/he deserves at this momemt.
You may think that you are working really hard and have to be paid a lot better. I have bad news for you: you are always getting the right compensation . You fill that you worth more? Just hit the job market and see if there is anyone else who also thinks so. Your manager is pretty sensitive to the current job market situation, and s/he tries to pay for your skills prevaling wage/rate.
If you believe that you can make more, tell this to your boss. Give him/her a chance to re-evaluate you compensation. If you won ‘t get any response from your boss, but someone makes you a better offer, quit without thinking twice. The chances are that when you give your two weeks notice (the industry standard), you current employer will offer you to match or even beat your new deal. Never ever accept the counter offer. You gave them a warning in advance, they ignored it, and now it ‘s too late. They just want to win some time to find your replacement. Sorry, guys. It ‘s a little too late.
Can ‘t find a better paid job in your town? Move to a different one. Can ‘t or do not want to? Do not complain – there is no such thing as underpaid people.