why i have to resist itching/tingling sensations what to do with these sensations,these happens all day,why i have to resist to itch   i am wondering when i can simply itch that move on.
The point is not to resist the urge. The meditation is in observing the effect the itch has on the mind. Satipatthana meditation is defined with three qualities: Ardency, Alertness, and Mindfulness. Let us focus on the first quality here. Though note that all three apply.

&quot;Ardency means being intent on what you're doing, trying your best to do it skillfully. This doesn't mean that you have to keep straining and sweating all the time, just that you're continuous in developing skillful habits and abandoning unskillful ones.&quot; - Thanissaro Bhikku

So in this context, we would want to itch in a skillfull way.
How does &quot;Simply itching and moving on&quot; effect us? How does giving into our urges when they come about serve us?
Does giving into the minds urges immediately lead you towards the goal or away from it? Each moment you are conditioning your mind (your kamma). Conditioning your mind to reactivity can lead to unskillful qualities if not done with headfulness.
I encourage you to scratch the itch and observe how your mind reacts. Then don't scratch it and observe it. Does there need to be discomfort because of the itch.
Recall the Five Subjects of Frequent Recollection:

Kammassakomhi kamma-dāyādo kamma-yoni kamma-bandhu kamma-paṭisaraṇo.

I am the owner of my actions, heir to my actions, born of my actions, related through my actions, and live dependent on my actions.

Yaṁ kammaṁ karissāmi kalyāṇaṁ vā pāpakaṁ vā tassa dāyādo bhavissāmi.

Whatever I do, for good or for evil, to that will I fall heir.

Evaṁ amhehi abhiṇhaṁ paccavekkhitabbaṁ.

We should often reflect on this.