Jangan risau too much, dear, perut kembung dan mengeras time 4 bulan ni actually quite common, sebab hormon progesteron masa mengandung ni memang akan slow down pergerakan usus kita, so senang kembung especially lepas makan. Kalau tahan kencing pun boleh tambah pressure kat perut, so try to go to the toilet more regularly and avoid eating too fast or too much at one time. My friend yang dah ada dua kids cakap dia selalu jalan-jalan slow-slow lepas makan to help with the bloating, and it really helped her. That said, since you're experiencing sakit too, it's always best to mention this to your doctor or O&G specialist at your next visit, just to make sure everything is okay with you and baby.