if after an interview I am called back to do a physical and a drug test does that mean if I pass I am hired?

unless something negative comes up you are hired.... a pre-employment drug screen is NOT at all expensive but a physical is..... since they are doing both the odds are in your favor that you are hired.

Generally speaking, yes, it means you have the job pending the results of the drug test and physical. Keep in mind, however, that it is not 100%. Any testing an employer requests costs them money. To have every applicant submit to those tests can get very costly. Especially in today's world, no business wants to pay for tests that ultimately are not going to produce some type of return (ie, your employment). That said, I have know companies to narrow their search to a handful of people and have them start drug testing, etc. The expectation is that some might fall out of the selection process due to those tests. Some companies would rather keep their options open before making their decision to avoid offering the job to someone and have to revoke it and start all over with someone else. Most companies, though, do offer a conditional hiring pending on the test results and it is fair for you to ask them when you are contacted if that is the situation you are in.