As a sixth-former (17-19 yrs old) I used to train with a bunch of other lads. We routinely ignored dangers that we were warned about and - thankfully - suffered little for it. Now that I'm in my mid-40s I can confidently say that your body is pretty good at telling you what is dangerous and what is not. I certainly wouldn't recommend that you do exercises you've been warned against, but you could try the following approach:

1. Start off with very light weights
2. Take it slowly and avoid all sudden or snatching movements
3. Stop as soon as you experience pain (normal muscle burn excepted)
4. Do a little at a time and wait to see if a problem arises

Of course, you have to ask yourself if the intended exercise is actually useful. There are often many ways to build a muscle group, so you don't need to take risks.

The occasional aches and pains I suffer can be linked to traumatic injuries (e.g. accidents, falls, impacts) and/or failure to prepare properly (e.g. running for 5 miles before getting used to running 2 miles).

Not aware of direct evidence, studies would have to account for flexibility at shoulder (rotator cuff, pectoralis, serratus) etc and in thoracic spine. Sports such as Olympic Weighlifting require this flexibility and regularly perform these movements. Strangely enough the technique varies only slightly from a dumbbell shoulder press or pulldown/chinup with two handles. The apparatus only moves another few inches rearward.  Can't see why this would be categorically bad all of a sudden? I believe that if you can perform these tasks with forearms vertical (and without exaggerrated thoracic and/or lumbar curves) potential injury is minimized at the shoulder joint. Performing the exercises with excessive weight (especially pulldowns/chins) and reduced range if motion can lead to excessive shoulder internal rotation especially on the eccentric portion, which could be problematic. Not aware if any research on damage to cervical spine (although it is often stated) and you don't hear anyone giving similar advice to barbell back squats normally done with MUCH heavier weights across the neck!