,Problems with capsule collider 2d and velocity

Ok this is a really weird bug i'm having for some reason my character (only when moving left to right) will randomly go up and down a bit on the y axis i believe it has something to do with the capsule collider as when i use a box collider its fine it will jut get caught on the groud which is why im not doing that it also happens with a cirle collider heres the code (by the way the comments are old lines of original code a wrote ages ago or stuf a commented out trying to find the bug source): using System.Collections; using System.Collections.Generic; using UnityEngine;

public class Player_Movement : MonoBehaviour { public Rigidbody2D rigidbody2D; public float m_speed; //public float gravity = 3f; public float midaircontrol = 1f; public Player_GC gC; public Bannana_Count bac; public Player_Jump pj; public Player_Health ph; public float display; //rigidbody2D.AddForce(new Vector2(0, -gravity), ForceMode2D.Impulse);

 private void Start()
 {
     rigidbody2D = GetComponent<Rigidbody2D>();
     
     
 }

 //rigidbody2D.velocity = Vector2.right * m_speed;
 void Update()
 {        

     //rigidbody2D.AddForce(new Vector2(0, -gravity), ForceMode2D.Impulse);
     if (Input.GetKey(KeyCode.A) && Input.GetKey(KeyCode.D) == false)
         {
         
         /*if (bac.SpeedChange == false)
         {
             m_speed = m_speed + (Time.deltaTime * 15f);
             if (m_speed >= 30f && bac.SpeedChange == false)
             {
                 m_speed = 30f;
             }
         }*/

             if (gC.Grounded == true)
             {
                 //if (pj.jumping == true)
                 //{
                     rigidbody2D.velocity = new Vector2 (-m_speed, rigidbody2D.velocity.y);
             display = rigidbody2D.velocity.y;
             Debug.Log(rigidbody2D.velocity.y + " A key");
             // }
             //else if (pj.jumping == false && ph.damagedoneM == false)
             //{
             // rigidbody2D.velocity = new Vector2(-m_speed, 0);
             // }
         }
             else if(gC.Grounded == false)
             {

                 rigidbody2D.velocity += new Vector2(-m_speed * midaircontrol * Time.deltaTime, 0);
                 rigidbody2D.velocity = new Vector2(Mathf.Clamp(rigidbody2D.velocity.x, -m_speed, +m_speed), rigidbody2D.velocity.y);
             }

         }
     

     else
     {
         if (Input.GetKey(KeyCode.D) && Input.GetKey(KeyCode.A) == false)
         {
             /*if (bac.SpeedChange == false)
             {
                 m_speed = m_speed + (Time.deltaTime * 15f);
                 if (m_speed >= 30f && bac.SpeedChange == false)
                 {
                     m_speed = 30f;
                 }
             }*/
             if (gC.Grounded == true)
             {
                 //if (gC.Grounded == true)
                 //{
                     //if (pj.jumping == true)
                     //{


                         rigidbody2D.velocity = new Vector2 (m_speed, rigidbody2D.velocity.y);
                 Debug.Log(rigidbody2D.velocity.y + " D key");
                 // }
                 //else if (pj.jumping == false && ph.damagedoneM == false)
                 //{
                 //rigidbody2D.velocity = new Vector2(m_speed, 0);
                 //}
                 //}
                 //rigidbody2D.velocity = new Vector2(m_speed, rigidbody2D.velocity.y);
             }
             else if(gC.Grounded == false)
             {
             
             rigidbody2D.velocity += new Vector2(m_speed * midaircontrol * Time.deltaTime, 0f);
             rigidbody2D.velocity = new Vector2(Mathf.Clamp(rigidbody2D.velocity.x, -m_speed, +m_speed), rigidbody2D.velocity.y);
             }
         

         }
         else
         {
             rigidbody2D.velocity = new Vector2(0f, rigidbody2D.velocity.y);

             if (bac.SpeedChange == false)
             {
                 //m_speed = m_speed - (Time.deltaTime * 10);
                 //if (m_speed <= 15f && bac.SpeedChange == false)
                // {
                     m_speed = 15f;
                 //}
             }
         }

         
     }
     




     /*if (Input.GetKeyDown(KeyCode.A) && gC.Grounded == false)
     {
         //rigidbody2D.AddForce(new Vector2(-m_speed, 0), ForceMode2D.Impulse);
         
         rigidbody2D.velocity = new Vector2(-m_speed, rigidbody2D.velocity.y);

     }

     if (Input.GetKeyDown(KeyCode.D) && gC.Grounded == false)
     {
         //rigidbody2D.AddForce(new Vector2(-m_speed, 0), ForceMode2D.Impulse);
         
         rigidbody2D.velocity = new Vector2(m_speed, rigidbody2D.velocity.y);
     }
    */ 
 }

}