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Both your primary and secondary telescope mirrors can easily shift during transport and collimation could easily be lost. You should ensure your telescope is properly collimated and then let us know if your are still having focus problems. Also ensure your 10mm eyepiece is clean and has no fingerprints or dust on the eye lens.
To check for gross collimation just look down the tube without an eyepiece installed. Rack out fully and insert the 2"/1.25" adaptor. Remove any cap from the front of the tube too and point the telescope at either blue sky or the garage ceiling, something with a uniform brightness (NOT THE SUN!). I find my white gyprock garage ceiling works well.
Look down the focusser and you should see your eye, the secondary, the primary & spider vanes reflected in the secondary but most importantly everything should be concentric. If not your telescope is out of collimation.
You can collimate approximately at least enough to give you proper focus with your 10mm eyepiece without any collimation tools by simply tightening or loosening the primary mirror screws and by enusring the secondary is centrered under the focuser and showing the full primary mirror reflection and also showing the end of tube as a concentric ring.
Search for collimating a Newtonian on the web and you'll find lots of links. You may read about secondary offset but do not be concerned with it at this time. To get even better collimation you can invest in a Cheshire collimation tool or make a simple sight tube using an old 35mm film canister.
However if you cannot get a 10mm eyepiece to focus after basic sight collimation without any tools then you may have other issues and I suggest trying a different 10mm eyepiece.
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