In picture 2, there are joists resting on top of the doorway/lintel above the doorway. If you can get a camera up there with a ladder, you may find a steel lintel hidden behind the blockwork to support whatever is on top of the joists (be it the roof or another floor of the property) If there is a steel lintel hidden and it is supported on both sides by blockwork and not just the timber studwork on the left, then you should be ok to remove the studwork to open the doorway further without needing to get someone in to fit a replacement lintel across the doorway to support the weight from above.

Regardless of whether there is a steel lintel hidden behind the blockwork, I would suggest (like others already have) you get professional eyes on the problem to give you complete peace of mind before doing anything structural to your property.