On our shared hosting accounts, we have certain limits in place to ensure quality of service and to prevent any one account abusing the server resources. If you feel your own account is using up all resources available to it, you can check this via your cPanel.
Once logged in to your cPanel, click on the icon for ‘CPU and concurrent connection usage’ (under the Metrics heading). You will be able to tell from the graphs how much resources you account is using and if you are reaching/exceeding the limits. Reaching these limits can be the result of a high volume of traffic on your website and/or the website itself using up alot of resources (regardless of visitor numbers). If you have not made any recent changes to this website, it is most likely the former cause.
Please do not hesitate to get in touch with our Sales team and they will be happy to advise on your upgrade options.