Hi Andrew. You may be underpaid … but I’ve yet to meet the person in business who felt she or he was overpaid. If you feel you are worth more, why not ask for it – or look for another job offer which will give you what you feel you’re worth?
You don’t indicate what country, let alone what market you’re in, but most industrialised countries publish national income data which gives comprehensive information on levels of employment and average earnings within different occupations, and perhaps there’s a professional assocation based where you are which can offer guidance?
In a market, a price is only a price when it has a willing buyer – your employer – and a willing (in the sense of accepting, rather than ecstatic) seller – in this case, you, selling your labour. So just what you bring to the party, and just what market conditions affect your employer’s business, will both be relevant here.