Why have i had trouble falling asleep and staying asleep?

Sleepless: Your question was cut off, but it seems that you have primary insomnia, assuming that you don't drink alcohol or use drugs, and that the problem has been there for a while. Recommend the sleep hygiene techniques (google that sentence & you get details), & if that fails, try low dose melatonin, & if that fails, see your pcp for other alternatives.

Sleep prolems: Possible causes of insomnia include: poor sleep hygiene,Traveling with change in time zones, chronic pain, frequent night-time urination, problems breathing, Shift work, anxiety disorders (esp. PTSD), Depression, bipolar disorder, stress, medications (i.e. stimulants), caffeine, alcohol, eating large amts before bed, aging, restless leg syndrome, sleep apnea, etc.

Identify reasons: If you can identify why you have trouble sleeping (anxiety, pain, etc.) then you correct the problem. I'd encourage you to read about proper sleep hygiene and keep a 2 week sleep diary. Examples are online that you can google.

Talk to your doctor: Talk about this with your doctor. This can be a sign or depression and many other things.

Sleep Hygiene is Key: Retire & rise same time each day. Keep bedroom dark & cool & use only for sex & sleep. Turn off tv. No naps. Exercise regularly but not in late evening. No caffeine for 6 hrs & no alcohol or tobacco w/i 2 hrs of sleep. Keep dinner moderate sized & finish at least 2 to 3 hrs before sleep. Can try warm milk, Chamomile tea or melatonin along w light reading, warm bath or lavender scent.