Slows down when opening the site (Bitrix), need help in solving the problem

Began to open a very long site on 1C-Bitrix, the first opening of seconds
30 is now. Its not entirely clear after what it happened, the work.
were made on the site more than a month ago, it seems that at that time there was no
Problems. In person I am ready to provide all the details. There is an interest to find
specialist for support and small improvements to the site on a regular
Basis.