Unfortunately you are in a no-win situation. In every band there are people who do more and those who do less and the pay situation is never fairly divided by workload (ask anyone who has ever worked with a girl singer). When you try to give yourself a "raise" it won't go over well and you won't be able to enforce it. Your bandmates aren't blind or stupid and they know full well that they are taking advantage of your enthusiasm and goodwill - they probably think it's funny. Don't even mention the unfairness of your situation to them unless you have an exit strategy planned. If I were you I'd polish my solo act.