Kudos Neem Clove Toothpaste

Gagging it is. Try to keep your head at little down position while brushing. When you look at front or upside while brushing, more chances are there, for the toothpaste or else to go at back and cause gagging. Plus amount of toothpaste you need is of pea size. Avoid excessive usage of that. Try and practise even without toothpaste some other time of the day. If brushing not helping much start with flossing and mouthwash as well.

if your kid have teeth in the mouth , yes, you can start tooth pastes like cheerio or kidodent. if teeth are not there, please use wet and clean soft clothes to gently clean the gums or gingivae.

Please tell me how you came to conclusion that it's a jaw pain but not tooth pain if your entire jaw is hurting then you have to take a video consultation for that probably it may occur due to third molar eruption.

Get scaling done n brush your teeth twice a day n use dental floss n mouthwash n do warmsaline rinces 3-4 times a day n scrap your tongue twice day n tel me d status after 5 days.

Yes you can use toothpaste apfter bleach. And if your teeth is yellow then you can go with snowhite tooth paste.