One, the coils and supressors go bad all the time. It's an electrical part and they just wear out. To get into the rhyme and reasons would require more detailed electrial theory than I care to get into on a web forum. It is not an uncommon thing at all, we replace them at my shop with some frequency. The others will probably be fine. Two, the tech "bumping"the coil would not cause it to fail. It would require intentional force to damage a piece like that, and you would have seen a cracked housing had this been the case. I would not worry about it.