We have an amana side by side. The coils froze then we frosted it. Now its froze again. What is causing it? Door seal seams good.

Frost will normally build up if you do not have frost free freezer and in which case it is possible the frost free system is faulty. If it is not frost free then it has to be defrosted a few times in a month. However if the frost comes up very quickly then there are possible causes.
You may be having leakage from the door seals or there are items in the freezer that are not properly covered to avoid moisture escaping. Other possibility is that your freezer is set too cold and there are not many items in it.

As far as your freezer frosting up, sounds like a door seal problem, run your fingers along the seam of the door seal, there should be no splits/holes in the seal.
As far as the refrigerator either there is a secondary fan motor, or there is a obstruction blocking the air movement, if the freezer has a bad seal, its suspect ice is still building up.

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It's usually caused by the condenser fan which is underneath around back. If it's not running when the compressor runs it will cause the problem you describe. You will need to remove the cardboard backing on the back of the fridge to access the fan.

make sure the damper vent door located between the freezer and refrige compartments is opening and letting in cold air from the freezer,if they ice up they can stick shut and not allow air flow,this door is behind a plastic grille an a hair dryer works great to defrost them

possible causes: bad door seals or condensate drain plugged causing evaporator coils (in freezer) to ice up, condenser or evaporator fans not on, condenser coils dirty, compressor not working, or a freon leak. if the back wall of your freezer is frosty or super cold, the coils are iced up. remove the back wall and defrost it with a hair dryer. if the water doesn't drain, unclog the drain tube. check the door seals for gaps. replace if necessary. check the fan in the freezer and the fan in the back. both should come on when the compressor is on. if not, check the fuses on the main board. replace if needed. if all that is fine, and there is no frost, you have a slow leak or a bad compressor. call in a pro or get a new fridge.

This excess frosting can be caused by leaky door gaskets, frequent door opening, dispenser door not closing good, anywhere air can get in. Gaskets should hold a dollar bill sung all the way around both doors.

It may not be sealing properly. check to see if a dollar bill will easly slide between the seal and the door. move the food ( and ice) away from the door then test with the dollar again. If it is not sealing clean with soap and watr using a dish brush. test again after drying. The last is to put a small amount of silicone greaseon the seal. The plumbing section section of the hardware store carries plumbers grease.

The frost should be uniform on the coils. Uneven frost pattern is a sign of low freon. Most systems are sealed but a qualified tech can recharge the system after finding the leak and cap it off.

you may have aburn out may be heater

The number one cause of freezers frosting up and especially that fast, would be that moisture is getting in.  The cause of this is more than likely that your magnetic seal around the door is not making a tight seal.  Check around the door and make sure it is sealed tight.  Even the smallest of gaps will make a big difference.  More than likely it is leaking on the side that has the most frost.  Hope this helps.