You can create a view called something like "My Items" with a filter that uses the "Assigned To" field (or whichever field it is that you want to filter out), the "is equal to" operand, and then in the text box below,
[Me] as the text you want to use.
[Me] tells SharePoint to use whoever is currently logged in to that context, and, in this case, to only return rows where the user object matches the current one.
This should require zero code and nothing more complicated than navigating to the list, opening the ribbon, selecting the List tab, and clicking on Modify View or Create View.
Here's a page (I always hated the "For Dummies" name but admittedly the series is often full of good, solid information) that explains this in some more detail: