Ay mama, ang cough after feeding at when awake is something you should mention again sa pedia, okay? Even if wala daw sa lungs, it's worth a second look kasi alam mo ang baby mo best, if it doesn't feel right to you, go back.
A few of us here noticed na sometimes yung position during feeding or how baby swallows can trigger coughing, pero hindi kami sure kung yan ba talaga. Since your pedia already checked him and okay ang breathing, that's good news, but if umuubo siya this frequently na worried ka, don't hesitate to get another opinion, walang mawawala sa peace of mind mo.
Karamihan sa amin sinusuggest din na if possible, video-record one of those coughing episodes and bring it sa next checkup para makita ng doctor exactly what it looks like. Mas nakakatulong talaga ang video, sobrang helpful.
Hang in there, mama, you're doing great monitoring him. Just trust your gut.