First the bad news: no, you cannot add RAM. And, if yours is the least expensive stock model, it has a snail like 5400 rpm spinning drive - and that would be the major part of your problem, especially using graphics apps. Please confirm your hard drive; FWIW the newer models have SSDs, not spinning drives. Unless you clone your internal to an external SSD and use that, there is nothing you can do except only run one app at a time and fix dinner while you wait for the rendering process.
And please, do not use all caps - it is difficult to read and considered shouting online.
You can download and run etrecheck which will give us an idea of what could be wrong - I am betting on the glacially slow hard drive. Adding RAM will not fix the problem. Use the third little icon from right to post it here.
www.etrecheck.com