How can migraine be cured? how can the pain be relieved immediately?

No easy answers but:: No drugs are known to "cure" migraines. Drugs like sumatriptan may give good relief IF taken shortly after onset. Once you have one pain meds can take the edge off but seldom give complete or immediate relief. The best strategy is preventive- avoid triggering foods;herbs like feverfew and butterbur often help-see https://tinyurl.com/zf6hg23 The closest to a cure may be individualized homeopathy.