1) I am using mycelium wallet on android for transfers, can i also use this as my main wallet?
You can if you want. It depends on how concerned you are about security.
i also have bitcoin wallet on my computer or do i have a few wallets?
You have mycelium on your phone and a bitcoin wallet on your computer? That means you have at least 2 wallets. I don't know if you have more wallets, you haven't told me.
2) Yesterday i started mining, but decided quickly it is not the best way to earn coins as the electricity bills out weigh the profits, so what is the best way to generate a decent some of coins? is it just to buy sell?
Just like with any other currency:
The best way is to figure out some product or service that you are able to provide that other people desire, then offer that product or service in exchange for an equivalent value of bitcoins. This is often called "commerce".
3) Also i looked at cex.io yesterday.... what the hell is that? is this the same kettle of fish so to speak?
Yes. It is a method of purchasing or renting mining from someone else.
4) Is it worth being sent 0.000005673 bit coins?
Right now? No.
If you hold on to them and bitcoin becomes extremely valuable some day, then they might be worthwhile. If you receive such payments in your wallet right now, and then your wallet attempts to use those receipts in some other transaction, it will cost you more in transaction fees than the amount you received. Therefore, such payments don't earn you money, they cost you money.
will my wallet show this figure in the transactions?
It depends on what wallets you are using. Some will, some won't. I'm not sure if mycelium will or not. Perhaps someone with more knowledge about mycelium will stop by with an answer.
