@Gracesgran
I agree with you that immigration causes problems in some quite small areas. However, leaving the EU wouldn't necessarily change that. EU immigrants tend to come to the UK for work, so they will naturally go to areas where there is work which suits them. There are relatively few EU immigrants on Mersayside, because unemployment is high. There is a high number of low-skilled immigrants in the East of England, because there is an abundance of farm work with few people wanting to do it. There are many immigrants in places such as Cambridge, because there are vacancies for high-skilled scientific, technological and medical staff...and so it goes on.
If we do leave the EU, Cambridge and the East of England will really suffer. People aren't suddenly going to want to do low paid farm work and the UK just doesn't have the high skilled people needed in Cambridge. Wealthier areas are going to struggle to find people to do work such as caring, cleaning and catering.
If businesses find that labour costs are too high in the UK, they will move abroad to places where costs are lower or they will go bankrupt, which means there won't be any jobs. This is what has already happened to much of British manufacturing and has nothing to do with the EU.