One of the frustrating problems that you might face with SharePoint 2013 applications is some of the errors that you really don’t know how to troubleshoot, or where to start your investigation, one of the errors I had is the following:
Error occurred in deployment step ‘Recycle IIS Application Pool’: Cannot connect to the SharePoint site: << Site Collection URL >>. Make sure that this is a valid URL and the SharePoint site is running on the local computer. If you moved this project to a new computer or if the URL of the SharePoint site has changed since you created the project, update the Site URL property of the project.
In my case I get the above error once you try to deploy my application, The above error is caused due to lack of permission of the current user on the content db of the Web Application. Add the current user to the db Owner role of the content database of the web application.