My problem is not so much in falling asleep but in staying asleep.
Insomnia is very common in our culture.
You're wise to try exercise and progressive relaxation. The syndrome of early morning wakening is one of the hallmarks of depression, so you might consider seeing your doctor or a therapist who is trained in diagnosing and treating depression. Many of the pharmacological sleep aids, whether prescription or over the counter, may interfere with REM sleep. You might try some of the more natural approaches that may help you relax and sleep more soundly. Valerian root extract has been shown to reduce sleep latency and increase sleep efficiency.