Doctor felt lump - follow up

Hi everyone. I am a 43 year old mom of 3. I am a bit concerned and need some help. So back in March, I went in to my routine OB visit. He felt a lump, so he scheduled me for a diagnostic mammogram and u/s. It came back negative and I had a follow up appt with him yesterday. He is concerned that the u/s technician didn’t even see anything when he can clearly feel this lump. The lump is still there by the way. He now wants me to see a breast specialist and he said more than likely they will do an mri. Is this normal? I am kind of freaking out. I thought he would be fine with the all clear from the mammo and u/s.

Just more info, I had a yearly mammogram on September 2020. All clear. Dr felt lump so went in and they did the 3D mammo and u/s back in March. Don’t you think of it was cancer or something they would have seen it? I am just really nervous because he doesn’t seem satisfied with the “negative” u/s and mammogram. Thoughts?