I noticed it when he was 3-4 months, now he's 6 m old. It only lasts a few seconds and it looks like a tremble of his head, it happens when he is almost asleep or asleep while breastfeeding or after a feed, when he is at my breast or being moved from the bed to his cot. It stops if I touch his head during the tremble. Until just recently he didn't seem to be bothered at all by this, he would just return to his sleep. Recently it happened on consecutive days while he was nursing but he wasn't fully asleep, his eyes were open, they did not roll back. It only lasts seconds, less than 5 seconds even, and when I touched his head it stopped. The last times though it seemed to bother him, he looked startled and he even cried and pushed away from the breast.
I am waiting for the paediatrician to come back to us to say if further investigation is needed. But I must admit I am really worried so I'd like to ask if there is anyone else whose LO has been through the same/ is going through the same, what was the treatment/outcome? Is it a long term issue or something temporary during infancy?
I'd really appreciate your responses, thank you. 
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