OP - Similar situation here. I need to be discrete at work, and must wear dress attire (tucked in shirt). I've also tried several of the "famous" IWB holsters, and found them to be very uncomfortable. In particular, sitting in a car was painful, as the seat pushed the pistol into my side. Ugh.
For pocket carry, the Shield is too big - the gip is too long. Also, you need a pocket holster with an anti-print panel.
If you insist on a 9mm pocket gun, then you're looking at the PM9/CM9, the Rohrbaugh R9, the Boberg XR9s or the DB9.
For pocket holsters, I use the Desantis Superfly, or leather pocket holsters from www.hiddenholsters.net. If you go with the latter, ask Jim for a thumb push-off.
In dress attire, I carry a PM9 plus a LCP in opposite pockets. If the pockets are on the smaller side, or the dress pants are too thin for the weight of the PM9, then I go with dual LCPs.
If you go with a .380, load it with a flat-nose FMJ and have no worries about it being able to ruin someone's whole day...
If you want to keep the Shield, then get yourself the Smartcarry. I've done presentations in front of large groups with a Glock 19 in mine, and no one noticed a thing.
I've gone to dual pocket carry mostly now, because it is even more comforable, and I like being able to discretely have a firing grip on my gun without being obvious about it.
Hope this helps, good luck.