The reason may be incorrect career planning. If your job is not in line with your long-term career plan (based on your interests), or if you don't even have a long-term career plan, then you need to sit down and think over your career and make decisions on which way you want to go? Should you continue to take up one job after another in a hit and miss fashion, without any clear plan? Or should you carefully choose the jobs you take based on where you want to be in, say, 10 / 15 years - the jobs that will help you achieve your goals? The latter will ensure a headache-free and more fulfilling career in the long-run as well as increase your earning potential, even if in the moment, it seems like a disadvantageous move.
Now you can plan your career path with our invaluable career guide - Mapping Your Career Path, available free simply by emailing firstname.lastname@example.org