I feel stinging pain under the nape, as if in the lower abdomen, but only under pressure. Sometimes I feel slight cramps and I have a terribly swollen stomach and a feeling of fullness and inflating. What's wrong with me?

Hi, for about three days I feel stinging pain under the nap, as if in the lower abdomen, but only under pressure. Sometimes I feel slight cramps and I have a terribly swollen stomach and a feeling of fullness and inflating. In addition to this, no other ailments. From additional information I will add that this pain began to appear during bleeding. I take Belara birth control pills (could this be their side effect?) The tablets I use regularly have never had any mishaps with them in the style of oblivion or vomiting, etc. I exclude pregnancy because I recently did a test- it came out negative, and I take these pills. Please advice on what it might be. I am starting to worry and unfortunately I do not have the opportunity now to consult a doctor, so I would like to seek any guesses or advice :(