my longtime girlfriend (mia noi) has been sick and coughing for 4 months.

she went to several hospitals and doctors and was never given an explanation but lot's of pills.

Finally, she went to the Chonburi hospital where whe was diagnosed with TB and told to avoid coughing and sneezing in public and to wear a mask. Also she was told not to kiss and not to have sex without condom.

My worry is, since she had this for the past 4 months and I had quite a bit of sex and kissing with her, should I go to a hospital and check for possible TB signs myself? (I do not have any symptoms though).

any advice?

Any known exposure is reason enough to get checked.

^Yep that was pretty simple and succinct, that's quite intimate contact for a fair period of time plenty enough reason to get checked out.. With such close intimate contact I'd consider starting a course of treatment even if it checks out ok at the moment because the TB bacterium (bacilli) can infect you and remain inactive without you developing symptoms until you actually get sick, which could be years on, as long as your immune system is healthy and protecting you..

TB facts

Most developed countries inoculate their teenagers against TB and have been doing so for decades, so if you're from such a country you may not be at risk. Thailand now routinely inoculates its children, too.

The disease is very contagious. My grandfather had it in the 60s and was keep in an isolation hospital for several months, until he was cured, to protect the general population.

Yes, you should be checked. In fact the hospital should have contacted all exposed people as part of the management (contact tracing) of TB as an infectious disease. A chest X-ray would be required. Skin tests will be of no value as it will probably be positive as a result of your contact with an infected individual. A positive skin test does NOT mean that you have active TB.