You can't sleep

Questions about insomnia, restless legs, and waking up tired

Could something MS-related be waking me up — spasticity, urinary issues, restless legs, pain?
Could my DMT or other medications be causing sleep problems?
Could this be restless legs? Should we check iron, ferritin, or vitamin D?
Should I have a sleep study?
Are there medications that could help without worsening fatigue? What are the trade-offs?
What sleep-hygiene changes actually help for MS?