There are many reasons, I would say first, change your oil to something a little thinner. if the shake is for more than a minute, you may want to have a mechanic look at the engine.
thick oil on a cold morning will all settle to the bottom overnight, and the pistons, rods, etc will all rub a bit, and give some vibration. if the oil is coating, it wont do that so much, and thinner oil will be easier on the oil oump in the morning when it is cold, and you should notice a difference.
if it does it longer than a minute, it may be the choke sticking, or a bad o2 sensor, or possibly an airflow sensor. a mechanic can tell you more specifically with the car in front of them, instead of "best guessing" it over the internet. if it only does it when it is cold, maybe leave it at the shop overnight, and meet them in the morning, and start it while they are there and let them see the shake you are describing.
The car shakes because your engin has been cold and you sudenly start the car it will shake
Cold start
only in the morning? cold morning, warm morning? how many miles do you get in you travels before this happens?
because its cold
shiver
The oil is cold in the morning
This is not a right sentence, She has a bad cold this morning. I have(First person) You Have(Second person) She/He Has(Third person)
on a cold morning the gas compacts and liquefy do to tempter thus your engine is not getting enough fuel to start
There could be many reasons why a car won't start in the morning. It might be a problem with a cold start, but it could be the battery isn't connected all the way, or the lack of gas.
how can i solve the problem
Your cold start sensor could be at fault, get a new one
They will shake sometimes when they are in pain.