My ankles and calves are aching at night. it came on a bit suddenly. what could cause that?

Need more info: most commonly this is the musculoskeletal pain from the build-up of tension from prolonged standing and walking, if aching feeling is relieved by leg movement consider restless leg syndrome, if aching is not better with movement may be a peripheral neuropathy, in which case you need to see a neurologist and get emg/ncs if warranted by more detailed history