My DM and I were discussing this, and he asked me to search for it/post it here. I looked around, but couldn't really find anything that discussed this issue specifically.
The description of Concentration is:
Some spells require you to maintain concentration in order to keep their magic active. If you lose concentration, such a spell ends.
If a spell must be maintained with concentration, that fact appears in its duration entry, and the spell specifies how long you can concentrate on it. You can end concentration at any time (no action required).
Normal activity, such as moving and attacking, doesn't interfere with concentration. The following factors can break concentration:
Casting another spell that requires Concentration. You lose concentration on a spell if you cast another spell that requires concentration. You can concentrate on two spells at once.
The section goes on to outline two more things that can break concentration; Taking Damage, and Dying. It is this first one that we were discussing.
Lets say that I cast Darkness (Which has the Concentration Tag). On my next term can I cast Shatter (Which does NOT have the Concentration Tag), without ending the Darkness Spell?
The wording seems to indicate that you CAN do this, But I've had several other DnD Players tell me that you can't.