What causes teeth pain and gum weakness and what shoud i eat and drink to avoid the pain and make my gum and teeth stronger ?

See\Discuss with DDS: Tooth pain can be caused by many things. At your age i would guess that the most likely cause would be dental caries (cavities). At your age, you should not have any serious gum problems. See your dentist for a complete and thorough examination to see what is wrong. At that point you can discuss both treatment and preventing problems for the future.

Bacteria: Teeth hurt? May be cavities and/or malocclusion. Gums "weak", sore, bleed? May be gum disease. Sounds like you should see dentist for thorough exam, cleaning, hygiene instruction, diet review, and possibly cavity & gum disease repair. Dentistry isn't expensive...Neglect is. You need a dentist, not a computer, not a pill, not a supplement. See a pro.