I have 7 canker sores in my mouth at once and is very annoying, any suggestions on what could be the cause?

Canker sores. Canker sores are the most common oral lesions. Individual ulcers typically last 1-2 weeks. The condition is idiopathic (cause is not known) recurrent aphthous ulcers is usually self-limiting and no treatment required. If concerned see your dentist after 10 days.
Canker Sores. Canker sores are small shallow ulcers that appear in the mouth that makes eating and talking uncomfortable. There are 2 types simple and complex. The cause of canker sores is unknown but many clinicians feel stress, certain foods (such as lemons, oranges, pineapples, apples, figs, tomatoes, and strawberries) can trigger a canker sore. Canker sores usually lessen in a few days & heal on their own.
Prevention. Canker sore or more specifically aphthous ulcer can be prevented by avoiding a common foam detergent found in most toothpastes called sodium laurel sulfate. Switching to biotene or other toothpaste not containing this ingredient can be the cure in preventing this painful condition.