Sounds like it needs repointing if no bricks are cracked. And if it’s older brickwork.

If the cracks are in a diagonal line then this is just normally settlement if the crack is vertical through the brick or block then this is what called a broken back where the foundation have broken if the cracks are horizontal these normally only occur around the heads of windows or openings where the incorrect lintel has been use or in older property's maybe no lintel,
As for the hole in the morter this could just be where the bricklayer never perped the joint properly or even an insect burrowing unless you have any other visual signs inside the property I wouldn't worry to much just keep an eye if things deteriorate then seek professional advise,
Without seeing the problem unfortunately it's a guessing game we can only.assume by your comments, if you would like it investigated please contact us through the channels provided.

Kind regards
ejr pro build

Sounds like it needs repointing if no bricks are cracked

Depends on the cracks. If they are randomly positioned throughout the wall then probably just a case of a rake out and repoint. If you are experiencing long cracks crossing multiple courses of masonry then this is most likely subsidence. This is a more extensive fix but still very achievable