Can carpal tunnel make it feel like there's something in your wrist that's stopping you from being able to fully bend it backwards ?

Hand position: Carpal tunnel typically worsens when bending the hand into extreme positions. Usually worse at night and with holding objects such as a car steering wheel.

No. See Hand MD: No. If you have a feeling of restriction of wrist extension then you may have a dorsal wrist ganglion. Schedule an appointment with a hand surgeon as s/he will best be able to examine and give you advice.