Yes It can be due to Chronic constipation.Please let me know if there is passing of mucous like secretion before or after defecation if yes its likely due to chronic constipation.The reason is due to chronic constipation there may be partial obstruction and these symptoms may have seen for confirmation you need to do CT scan or colonoscopy.please consult qualified surgeon for the same.

Consult ayurveda physician for proper diagnosis and root cause of ailments before consuming any medicine

In Ayurveda this is Adhmana - due to vitiated Apana Vata & Mandagni. Trapped gas, heaviness at night while lying down and incomplete evacuation are signs of Vata-anulomana vikruti.

Consult for proper treatment plan personally on practo.

Hingvastakchurnafter food,avipatikar churn has good result.take triflachurnwith lukewarm water at night before sleep for constipation.

The symptoms you describe—abdominal bloating, pressure/tightness, difficulty passing gas and worsening of symptoms at night or while lying down—can occur with constipation, excessive intestinal gas, IBS or altered bowel motility. Sometimes stool retained in the colon can also make it difficult to pass gas comfortably. The fear of stool passing with gas can further lead to repeated straining and increased abdominal/pelvic tension. From an Ayurvedic perspective, such symptoms may be associated with disturbance of Apana Vata and impaired digestive function, but the exact cause should be assessed from your bowel pattern, diet and lifestyle.

You can use avipattikar kar churn at night after meal 1 tsf and kamdudha ras 2 tab for 15 days