By deafult, when customer/user log in Magento, he/she is redirected to its account page.

But if you’d like to redirect the customer back to the product/page he was visiting before.

Login to Magento Admin.

Go to System -> Configuration -> Customer Configuration -> Login Options.

From the drop-down select “no” and save configuration.

Refresh the cache and try to login.

Hope! you will enjoy.