You have a problem with either your gums and/or your tooth (teeth). When a cavity is near the center nerve,artery and vein complex called the chamber you can have pain with hot, cold, and sweets. Some times the gum area can also be involved. When you are having pain with a tooth, the pain and may go away for a while, and then returns. If your nerve is involved you can have an infection that is chronic and bacteria and their toxins are in your blood vessels circulating all over your body. Visiting your dentist to find out what's happening. We can answer your questions and give possible solutions but we don't have x-rays or other information. Pain in a tooth is telling you something is wrong.

Not always the case, please visit your dentist to have an evaluation

Looks like a cavity. See your dentist.

Yes. See a dentist for treatment.

Hi there
Yes it definitely sounds like you have a cavity and possible a deep one. Sensitivity to hot usually suggests a deep cavity close to or involving the nerve.
Pain on pressure and keeping you at night are 2 other signs suggestive of deep decay requiring root canal. Do visit your dentist . Hope this helps.

A cavity is one possible cause of a toothache and sensitivity to hot cold and sweets. Other possible causes could be a cracked tooth, loose or leaking filling, a filling that fell out, receding gums, grinding or clenching your teeth, and trauma. You should make an appointment with your dentist and have him of her do a thorough examination and take appropriate xrays in order to figure out what is causing your tooth pain.