Hello. I can understand your distress.
Having a tight foreskin opening that causes discomfort while erections, during intercourse or when you try to retract it, this can be a problem of phemosis. Although I would require more information to ascertain the condition.
Sensitive penis head is very normal, it gets better with time. Don't worry about that.
Next Steps
You may reach to me directly here on practo for detailed explanation on management and treatment. or you may visit a nearby doctor and get yourself examined.