Can it be a sign of colon problem.

Respect doctors, I have persistent abdominal discomfort for the last 4 months. It feels like pressure (not pain)... And it feels bit tender on the skin towards the left end of the rib cage. It is more evident when I inflate my belly. It feels like a pressure around (upper left). If I lie down my arm on that part it feels more sensitive than the right part. Since my childhood days I have an oversensitive bowel. When stressed or if I have to go to some place I will pass the stool two to three times. I usually have loose stools. My height is 174 cm and since past 2 - 3 years I have been overweight over 105 kg (earlier I was 78kg). I have changed my diet completely and started exercising (not regular). But since last 3 months 10 days I almost lost 11 kgs. I have been anxious regarding several health aspects. I suspected something with Colon and showed the doctor (GI) he told me possible IBS and stress. I have done CECT and attaching the report along with my stool (not sure of changes).