I am getting "access denied" error to SharePoint site, even after getting
full control access to the site.
I have cleared all the cookies and browsing history and checked in IE, but getting the same error.
Do you have any third party control deployed ? Try giving access to root site for the web app .... sometimes some data might be access from root site and you don't have access to that site.
i.e. if your current site is
Use Fiddler to capture the http/https traffic, navigate to your site and look for HTTP 401 errors. It will point you to the exact element causing problems. Note that 401 responses are normal when using NTLM. It is essentially the server requesting an authentication header to a secured resource. So, HTTP 401 responses followed by HTTP 200 are fine and should be ignored.