I keep almost fainting? should i get tests for deep vein thrombosis?

Probably not: Although there are many things that can cause near syncope (almost fainting), deep venous thrombosis would not be anywhere close to the top of the list. If you have leg pain and swelling, think about a DVT but if your legs feel fine, other things should probably be evaluated first.

Fainting: If you are repeatedly fainting, then you need to have a clinical examination and probably some testing to determine the cause. While there could be a DVT in your history, there are many more questions that need to be asked so that an appropriate work-up can be initiated.