Cant hear any sound anymore

See this link for possible solutions, but if none work, it's time to schedule a visit to your Apple Store Genius Bar for evaluation and options --> If you hear no sound or distorted sound from your iPhone, iPad, or iPod touch speaker - Apple Support

You Know, I had this same problem with my iPad, have you listened to any harmful music, There are some really bad music that can kill speakers slowly, Never watch those videos. Get it repaired at an Apple Store, Or best Upgrade, Your phone seems like in 2020 your phone will be dead in support and updates. Hope this helps