Agoraphobia is when you avoid going places for fear of having a panic attack. Your world gradually becomes smaller. Then the agoraphobia makes you depressed because you're not going out and enjoying yourself as you used to. Then you fear the depression and that adds to the anxiety that makes the agoraphobia worse and so and so on.
Sometimes agoraphobia is selective. You can go out to certain places you feel comfortable along familiar routes. Sometimes your ok if you go someplace with someone.
In some cases you fear going out to an appointment that you must attend but if you get through it without a panic attack you get a boost of confidence and stay out longer maybe even into a busy shop!
Sometimes you go someplace new and curiosity overtakes the anxiety and you return feeling good. But if you do that same journey again with no curiosity the anxiety will take over. So its difficult.
Sometimes you need a warm up. Go somewhere that will slightly boost your anxiety then come back slowly so much that you enjoy the journey back. then go to another place that would have seemed impossible at the start and you may find that you can do that without fear!