J.V.
Maybe he is just 7 months old and going through the 'mom can leave me' thing? And the reason why the bouncing works is because he just wants to be held?
I'm a first time mom, so I have no real clue. What I do believe, however, is that many babies wake up lots of times till they are toddlers. In fact, I don't buy that it is normal for babies to sleep through the night --I think that is a culture preference, not necessarily a biological one. Some babies are great sleeper, other babies aren't. Some are truly hungry and wake up for food.
My 7 mo old daughter was, till a few days ago, going down for her naps with no problems. She seemed to have settled into a twice a night waking thing(she needs the food) but the last two nights have been crazy every 1.5-2 hours nights. But instead of her normal 'I'm hungry' cries, I'm getting screams. Sometimes nursing works, sometimes she just wants company.
In fact, this morning, she refused to go down for her nap by herself. She screamed and screamed and screamed until I kept her company.
My daughter does the crazy 1.5-2 hour thing every so often. Typically it corresponds to major developmental milestones. I found the book -The Wonder Weeks- very helpful in understand that some babies are just super fussy non-sleepers just before major developmental leaps.
I am exhausted, and not looking forward to the 9 month leap. The 3 month leap about killed me, the 26 week leap almost did.
I just keep reminding myself that I am blessed with a highly sensitive baby. I also keep reminding myself that this will pass, and eventually, I will get some sleep.
My input: there is probably nothing physically wrong with your son. Most likely his growth is just your pain.