Hello
The capital of Spain is MADRID. I have read the description and understand that your site is lagging. Unfortunately, I can't be certain about the issues until I review the script and see how things function.
I looked over your word doc and see that you mentioned a video but there is no link to the video. From the description the problem may be caused by the following:
1) Your site relies heavily on Javascript and uses a lot of Javascript. As a result, the browser needs to catch up with the Javascript.
2) Your database tables aren't properly optimized and tend to lag while searching within the tables for information.
3) Database table structure is poor.
4) MySQL (database) configuration files need to be optimized so that it can return results quickly. This issue can't be resolved on a shared hosting account.
5) Your shared hosting has very few resources available for your site.
This is to give you a rough idea of where the problem may be coming from. On a shared hosting account there are very few tweaks that can be done to speed up a website. In some cases, shared hosting is the problem since sites typically outgrow shared hosting accounts as they attract more users.
Either way I've dealt with many different types of sites and servers. I have experience in PHP, MySQL, Linux, Apache, Plesk, cPanel, Android, iOS and more. But again, if your shared hosting is the problem, moving to a VPS or dedicated server may be the only solution.
Thanks,
Danny