Good advice above. Both chucks and ribs are trickier than brisket in terms of tenderness. Both need to be cooked longer than you think it needs compared to brisket when starting out. You don't want brisket cooked to pullable temps, but chuck you do want pullable, so there's the reason for that one taking longer. For ribs, it's about the sheer amount of connective tissue. It will start to probe tender, but really, until the meat is about ready to just pull apart from the bone it's still going to have quite a bit of chew.
Keep plugging away. It can be frustrating while mastering it, but once you got it, things are a lot smoother sailing from then on in general (although you will still screw up now and then).