Over the years, there have been many banned substances in athletic competitions

Over the years, there have been many banned substances in athletic competitions — many for obvious reasons, such as steroids, which would give an athlete a competitive edge due to unnatural muscle enhancements (as well as possible aggressiveness).
Morphine (narcotic painkiller) is a banned substance at competitive athletic events. Yet if an athlete experiences pain while training, there is no ban on using morphine to dull the pain throughout training. And studies have shown that if the athlete gets their last morphine injection shortly before the event, and a saline injection the day of the event (so they test negative for morphine), their body still feels the positive effects of the morphine. if you’re used to taking your painkiller all the time during training or games, and you can’t have it the day of your event, how would that affect your body? Do you think that all narcotic painkillers be prohibited in competitive events? Why or why not? I want you to elaborate further on why you think morphine should or shouldn’t be banned from competitive athletic competitions.
Pain killers are often used by everyone so please include your own personal opinion if you have ever used morphine for headaches etc, did it affect your everyday regular activities?
Feel free to look up any articles and references! There are many abused drugs in competitive sports, compare Morphine to the rest and discuss why morphine is less/more harmful than the rest for example(caffeine, and erythropoietin (Lance Armstrong was famous for using/abusing EPO.)