Trouble Going Poo

I'm almost 3 Months PP and I have the hardest time pooing ... I was prescribed stool softener after birth and I bought some as well for when the prescription runs out . So far nothing has worked! I've even tried laxatives which only gave me cramps that I assumed meant It was time to go poo so I sat on the toilet and it was just as painful as any other time .. I honestly feel like I'm pooing razor blades or shards of glass !! So my question , is this due to birth ? Has this happened to anyone else ? Any tips on how to have softer stool ?