Gingivitis. Or general physician?

Hello. Looking the pictures you have provided, no ulceration is visible as such except in the guma related to your left lower 1st molar (though the picture is not clear so can't comment accurately). It would be better if you can tell the area of mouth where you have noticed the ulcers. But apart from that, there is plaque formation (thin film of food particles and microbes) over your teeth near the gums which cause gingivitis (inflammation of gums), explaining the swelling. For that you will need to get scaling done from a dentist or a Periodontist (specialist of gum diseases). Plus, pain and swollen lymph nodes can also be due to any infection in your mouth or throat. So you need to go to a dentist first for thorough examination and scaling. If there are no abnormal findings which may lead to swollen and painful lymph nodes then you can visit an ENT specialist or General Physician.

Mouthrise with lukewarm water with a pinch of salt