My husband drinks 18 pack or sometimes 15 pack of beer per day. He's starting getting some pain in he's head. Is this a liver problem?

If it's not it will be soon. Sounds like he is fighting off unseen demons. 

My step dad had bladder cancer and had his whole inside's gutted from drinking his whole life and is stupid because of the fights he got into and punched in the head a few times at bar's and parties.

No-

It sounds like its a dehydration issue! Alochol will actually deplete your bodies water source, and when a person doesn't get enough water intake, it can cause headaches and migraines.

I can tell you this, if your husband doesn't smarten the **** up and quit his addiction, he will die from liver failure, not an "if", its a certainty! My grandfather used to pound them back (rye), anywhere from 10-20 a day, he'd start at 10am and go hard until 9pm at night, and I'm referring to non-mixed rye. He lived until his mid 80's, but, liver failure is what killed him.

Your husband needs to get some help.

If your husband continues drinking like he is everyday, he is going to end up with Cirrhosis of the Liver and will eventually die, a very slow and painful death.

Depending on how long this has been going on, then he may already have some Liver Damage. It would be a good idea to have him see his Dr. and get tested, to see if there had been any Liver Damage.

he has a wife problem...........

He probably has high blood pressure from all that alcohol. You don't say how old he is, but i"d drag his drunk a55 to the doctor now!

He's killing himself. It will only get worse.

buy the life insurance now . 

This is something for his personal physician to assess.  We cannot tell whether or not he's got a liver problem.  Chances are with all that beer drinking that he's not in optimal health, but NO one can tell over the internet without the medical history and a proper medical examination with blood works, what his medical issues are.  BTW, he qualifies as an alcoholic if he drinks that much beer per day!