What do I avoid after hernia op

I had a hernia op (ingenuil) 3 years ago- but I still sometimes feel it after gym- not sure if its recurrent or what.  I do many reps but with limited weight (e.g. bench press- 4 sets of 15 reps with 20-30 kg).  Pse advise if there are specific exercises that I should avoid and others that you would recommend.  Also any advice and  experience of people who still have 'hernia' problems years after the op..
 
Thanks