Player gets stuck into object when it collides with it

Hi, when I my player collides with an object it gets stuck and has a kind of jittery movement. The player does not have normal movement, it has a kind of blocky movement and I want it that way. The player has a rigidbody and a box collider the object only has a box collider. Please write the exact code I should use because I'm new to Unity. Here is my code below which is attached to the player \/

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerController : MonoBehaviour {
     [SerializeField]
     float speed = 2.0f;
     Vector3 pos;
     Transform tr;
     
     void Start() {
                 pos = transform.position;
                 tr = transform;
         }
          
     void Update() {
              
                  if (Input.GetKey(KeyCode.D) && tr.position == pos)
                      {
             pos += Vector3.back;
                      }
                  else if (Input.GetKey(KeyCode.A) && tr.position == pos)
                      {
             pos += Vector3.forward;
                      }
                  else if (Input.GetKey(KeyCode.W) && tr.position == pos)
                      {
             pos += Vector3.right;
                      }
                  else if (Input.GetKey(KeyCode.S) && tr.position == pos)
                      {
             pos += Vector3.left;
                      }
              
                  transform.position = Vector3.MoveTowards(transform.position, pos, Time.deltaTime * speed);
         }  
          
     }