What should one do who suffers from mental distraction and abdominal pain during prayer, which leads him to perform most of his prayers at home?

Satan is keen to spoil worship with whispers (waswas) and by making one think about matters outside of it, such as reminding one of needs during prayer or making one feel stomach pain to deprive the worshiper of congregational prayer. It is advised to see a doctor if the pain is real; otherwise, it is recommended to fortify oneself with dhikr (remembrance of Allah) and reading the Qur’an, not to succumb to these delusions, and to seek Allah's help in repelling them.