Gas blotting and piles. Manage my piles.

All the time my stomach feels heavy. I suffer from constipation every day, and my digestion has been causing problems for a long time. My stomach always feels bloated and uncomfortable. It often feels hot or irritated inside, and I frequently burp after eating. My bowel movements are hard, and I have to strain during bowel movements. Recently, I was diagnosed with Grade II piles, which I believe may be related to my chronic constipation. I work as a service engineer, so eating outside is unavoidable because of my job, making it difficult to maintain a healthy diet. Please advise me on the possible cause of these symptoms and suggest the best treatment, dietary changes, and lifestyle modifications to improve my digestion, relieve constipation, reduce bloating, and help manage my piles.