Hi there. Sometimes wall thickness can be a result of raised BP. How are your numbers? Do you take any BP meds? You will probably be sent for a heart cath. This invasive test will give a proper view of whats going on. A Cardiac MRI would be a good test also?
The fact that part of your heart is hypokinetic is probably caused by lack of oxygen to the heart muscle (ischemia).
The circumflex coronary artery feeds oxygen rich blood to the posterolateral wall of the heart, so if ischemia is found, that artery is most suspect for stenosis.
Your cardiologist will probably suggest further testing.