Pain in the gums from eating usually comes from a condition called stomatitis, in which inflammation and soreness occurs in the mouth, specifically with gum disease. In many cases, gum disease starts as gingivitis and then progresses to periodontal disease, but other factors may contribute to soreness in the gums, notes WebMD.
WebMD explains that stomatitis occurs inside any part of the mouth including the cheeks, gums, tongue, lips and palate. Mouth ulcers or aphthous ulcers, herpetic sores and mouth irritation usually cause stomatitis. In addition to gum disease, stomatitis from mouth irritation often stems from biting the cheek, tongue or lip. Wearing braces or another type of dental apparatus may also lead to pain in the gums and having a sharp broken tooth causes some pain. Burning the mouth from hot food and drink and chewing tobacco may lead to irritation in the gums as well. Hypersensitivity to foods and medicines may also lead to pain.
According to WebMD, afflictions such as autoimmune diseases, like Behcet's disease, Crohn's disease or lupus, affect the mucosal lining of the mouth, so the gums may become sore. Even treatments for diseases, such as radiotherapy for cancer treatment, or medications like chemotherapeutic agents, antibiotics and medicines for rheumatoid arthritis or epilepsy, link to gum pain.