The pill does not usually cause the symptoms you are experiencing. It is likely that you have chronic constipation
and incomplete emptying. You can take a laxative and see if you feel the emptying is complete. Otherwise, consult a gastroenterologist
and take advice. You may need to test your stool for infection as infection sometimes predisposes to tenesmus
. Also, you should get a local examination done to exclude local lesions. Take care.