Ay mama, during pregnancy talaga common ang side pain from sleeping position kasi ang bigat ng baby and ligaments are stretching, pero puwede rin mag-shift ang kidneys so better i-check mo with your OB para peace of mind, hindi dapat ma-dismiss, especially if matagal na or may fever. Try sleeping with a pregnancy pillow between your knees and under your bump muna, at iwasan ang malalim na tulog sa iisang side lang, pero definitely ask your doctor para sure!