Carlos, I'll let others keep talking about ukemi. My concern is:
Carlos Ordoņez wrote:
I've been practicing Aikido for 6 months now, .... I got hurt the first time I tried, I almost ripped a ligament in my shoulder and it hurts since then.
An injury needs 6 ot 8 weeks to heal. That you continued to train with it/through it means that you never let it heal and have given yourself a chronic injury. It may wax and wane in how much it bothers you but will likely never be "better."
Please be kind to your body and give it what it needs to heal.